diff --git a/build/org.eclipse.cdt.managedbuilder.core/plugin.xml b/build/org.eclipse.cdt.managedbuilder.core/plugin.xml
index 1dfa50414a5..d31eb74f7a9 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/plugin.xml
+++ b/build/org.eclipse.cdt.managedbuilder.core/plugin.xml
@@ -349,7 +349,7 @@
       	</inputType>
       	<option
       		id="org.eclipse.cdt.build.core.settings.holder.incpaths"
-      		name="include paths"
+      		name="Include Paths"
       		browseType="directory"
       		valueType="includePath"
       	/>
@@ -370,6 +370,31 @@
       		browseType="file"
 			valueType="includeFiles"
       	/>
+
+      	<option
+      		id="org.eclipse.cdt.build.core.settings.holder.undef.incpaths"
+      		name="Undefined Include Paths"
+      		browseType="directory"
+      		valueType="undefIncludePath"
+      	/>
+      	<option
+      		id="org.eclipse.cdt.build.core.settings.holder.undef.symbols"
+      		name="Undefined Symbols"
+			valueType="undefDefinedSymbols"
+      	/>
+      	<option
+      		id="org.eclipse.cdt.build.core.settings.holder.undef.symbolfiles"
+      		name="Undefined Symbol Files"
+      		browseType="file"
+			valueType="undefSymbolFiles"
+      	/>
+      	<option
+      		id="org.eclipse.cdt.build.core.settings.holder.undef.includefiles"
+      		name="Undefined Include Files"
+      		browseType="file"
+			valueType="undefIncludeFiles"
+      	/>
+
       	<!--option
       		id="org.eclipse.cdt.build.core.settings.holder.includes"
       		name="holder for includes"
diff --git a/build/org.eclipse.cdt.managedbuilder.core/schema/buildDefinitions.exsd b/build/org.eclipse.cdt.managedbuilder.core/schema/buildDefinitions.exsd
index 57ecbeb1510..fb3e0ced7e4 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/schema/buildDefinitions.exsd
+++ b/build/org.eclipse.cdt.managedbuilder.core/schema/buildDefinitions.exsd
@@ -1213,6 +1213,18 @@ Additional special types exist to flag options of special relevance to the build
                   </enumeration>
                   <enumeration value="libFiles">
                   </enumeration>
+                  <enumeration value="undefIncludePath">
+                  </enumeration>
+                  <enumeration value="undefDefinedSymbols">
+                  </enumeration>
+                  <enumeration value="undefLibPaths">
+                  </enumeration>
+                  <enumeration value="undefLibFiles">
+                  </enumeration>
+                  <enumeration value="undefIncludeFiles">
+                  </enumeration>
+                  <enumeration value="undefSymbolFiles">
+                  </enumeration>
                </restriction>
             </simpleType>
          </attribute>
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IOption.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IOption.java
index 5e4359d658f..aed20c48d9e 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IOption.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/IOption.java
@@ -29,6 +29,13 @@ public interface IOption extends IBuildObject {
 	public static final int LIBRARY_PATHS = 9;
 	public static final int LIBRARY_FILES = 10;
 	public static final int MACRO_FILES = 11;
+
+	public static final int UNDEF_INCLUDE_PATH = -INCLUDE_PATH;
+	public static final int UNDEF_PREPROCESSOR_SYMBOLS = -PREPROCESSOR_SYMBOLS;
+	public static final int UNDEF_INCLUDE_FILES = -INCLUDE_FILES;
+	public static final int UNDEF_LIBRARY_PATHS = -LIBRARY_PATHS;
+	public static final int UNDEF_LIBRARY_FILES = -LIBRARY_FILES;
+	public static final int UNDEF_MACRO_FILES = -MACRO_FILES;
 	
 	// Browse type
 	public static final int BROWSE_NONE = 0;
@@ -69,6 +76,13 @@ public interface IOption extends IBuildObject {
 	public static final String TYPE_LIB_FILES = "libFiles"; //$NON-NLS-1$
 	public static final String TYPE_INC_FILES = "includeFiles"; //$NON-NLS-1$
 	public static final String TYPE_SYMBOL_FILES = "symbolFiles"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_INC_PATH = "undefIncludePath"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_DEFINED_SYMBOLS = "undefDefinedSymbols"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_LIB_PATHS = "undefLibPaths"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_LIB_FILES = "undefLibFiles"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_INC_FILES = "undefIncludeFiles"; //$NON-NLS-1$
+	public static final String TYPE_UNDEF_SYMBOL_FILES = "undefSymbolFiles"; //$NON-NLS-1$
+	
 	public static final String VALUE = "value"; //$NON-NLS-1$
 	public static final String VALUE_TYPE = "valueType"; //$NON-NLS-1$
 	public static final String VALUE_HANDLER = "valueHandler"; //$NON-NLS-1$
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedBuildManager.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedBuildManager.java
index bb0422d0e92..81f6d29c4b3 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedBuildManager.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedBuildManager.java
@@ -863,6 +863,12 @@ public class ManagedBuildManager extends AbstractCExtension implements IScannerI
 							&& option.getValueType() != IOption.LIBRARY_PATHS
 							&& option.getValueType() != IOption.LIBRARY_FILES
 							&& option.getValueType() != IOption.MACRO_FILES
+							&& option.getValueType() != IOption.UNDEF_INCLUDE_PATH
+							&& option.getValueType() != IOption.UNDEF_PREPROCESSOR_SYMBOLS
+							&& option.getValueType() != IOption.UNDEF_INCLUDE_FILES
+							&& option.getValueType() != IOption.UNDEF_LIBRARY_PATHS
+							&& option.getValueType() != IOption.UNDEF_LIBRARY_FILES
+							&& option.getValueType() != IOption.UNDEF_MACRO_FILES
 							)) {
 				return;
 			}
@@ -890,6 +896,12 @@ public class ManagedBuildManager extends AbstractCExtension implements IScannerI
 					&& option.getValueType() != IOption.LIBRARY_PATHS
 					&& option.getValueType() != IOption.LIBRARY_FILES
 					&& option.getValueType() != IOption.MACRO_FILES
+					&& option.getValueType() != IOption.UNDEF_INCLUDE_PATH
+					&& option.getValueType() != IOption.UNDEF_PREPROCESSOR_SYMBOLS
+					&& option.getValueType() != IOption.UNDEF_INCLUDE_FILES
+					&& option.getValueType() != IOption.UNDEF_LIBRARY_PATHS
+					&& option.getValueType() != IOption.UNDEF_LIBRARY_FILES
+					&& option.getValueType() != IOption.UNDEF_MACRO_FILES
 					))
 				return;
 		} catch (BuildException e){
@@ -919,6 +931,12 @@ public class ManagedBuildManager extends AbstractCExtension implements IScannerI
 				&& option.getValueType() != IOption.LIBRARY_PATHS
 				&& option.getValueType() != IOption.LIBRARY_FILES
 				&& option.getValueType() != IOption.MACRO_FILES
+				&& option.getValueType() != IOption.UNDEF_INCLUDE_PATH
+				&& option.getValueType() != IOption.UNDEF_PREPROCESSOR_SYMBOLS
+				&& option.getValueType() != IOption.UNDEF_INCLUDE_FILES
+				&& option.getValueType() != IOption.UNDEF_LIBRARY_PATHS
+				&& option.getValueType() != IOption.UNDEF_LIBRARY_FILES
+				&& option.getValueType() != IOption.UNDEF_MACRO_FILES
 					)) {
 				return;
 			}
@@ -3562,6 +3580,26 @@ public class ManagedBuildManager extends AbstractCExtension implements IScannerI
 		case IOption.MACRO_FILES:
 			return ICLanguageSettingEntry.MACRO_FILE;
 //		case IOption.LIBRARIES:
+//			return ICLanguageSettingEntry.LIBRARY_PATH;
+		}
+		return 0;
+	}
+	
+	public static int optionUndefTypeToEntryKind(int type){
+		switch(type){
+		case IOption.UNDEF_INCLUDE_PATH:
+			return ICLanguageSettingEntry.INCLUDE_PATH;
+		case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+			return ICLanguageSettingEntry.MACRO;
+		case IOption.UNDEF_INCLUDE_FILES:
+			return ICLanguageSettingEntry.INCLUDE_FILE;
+		case IOption.UNDEF_LIBRARY_PATHS:
+			return ICLanguageSettingEntry.LIBRARY_PATH;
+		case IOption.UNDEF_LIBRARY_FILES:
+			return ICLanguageSettingEntry.LIBRARY_FILE;
+		case IOption.UNDEF_MACRO_FILES:
+			return ICLanguageSettingEntry.MACRO_FILE;
+//		case IOption.LIBRARIES:
 //			return ICLanguageSettingEntry.LIBRARY_PATH;
 		}
 		return 0;
@@ -3585,6 +3623,23 @@ public class ManagedBuildManager extends AbstractCExtension implements IScannerI
 		return 0;
 	}
 	
+	public static int entryKindToUndefOptionType(int kind){
+		switch(kind){
+		case ICLanguageSettingEntry.INCLUDE_PATH:
+			return IOption.UNDEF_INCLUDE_PATH;
+		case ICLanguageSettingEntry.INCLUDE_FILE:
+			return IOption.UNDEF_INCLUDE_FILES;
+		case ICLanguageSettingEntry.MACRO:
+			return IOption.UNDEF_PREPROCESSOR_SYMBOLS;
+		case ICLanguageSettingEntry.MACRO_FILE:
+			return IOption.UNDEF_MACRO_FILES;
+		case ICLanguageSettingEntry.LIBRARY_PATH:
+			return IOption.UNDEF_LIBRARY_PATHS;//TODO IOption.LIBRARIES;
+		case ICLanguageSettingEntry.LIBRARY_FILE:
+			return IOption.UNDEF_LIBRARY_FILES;
+		}
+		return 0;
+	}
 	public static ICConfigurationDescription getDescriptionForConfiguration(IConfiguration cfg){
 		ICConfigurationDescription des = ((Configuration)cfg).getConfigurationDescription();
 		if(des == null){
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedOptionValueHandler.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedOptionValueHandler.java
index 011b4eb0671..f180889300c 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedOptionValueHandler.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/core/ManagedOptionValueHandler.java
@@ -119,6 +119,7 @@ public class ManagedOptionValueHandler implements
 					}
 					break;
 				case IOption.INCLUDE_PATH:
+				case IOption.UNDEF_INCLUDE_PATH:
 					if (Arrays.equals(option.getIncludePaths(), (String[])defaultValue)) {
 						return true;
 					}
@@ -129,6 +130,7 @@ public class ManagedOptionValueHandler implements
 					}
 					break;
 				case IOption.PREPROCESSOR_SYMBOLS:
+				case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
 					if (Arrays.equals(option.getDefinedSymbols(), (String[])defaultValue)) {
 						return true;
 					}
@@ -147,6 +149,10 @@ public class ManagedOptionValueHandler implements
 				case IOption.LIBRARY_PATHS:
 				case IOption.LIBRARY_FILES:
 				case IOption.MACRO_FILES:
+				case IOption.UNDEF_INCLUDE_FILES:
+				case IOption.UNDEF_LIBRARY_PATHS:
+				case IOption.UNDEF_LIBRARY_FILES:
+				case IOption.UNDEF_MACRO_FILES:
 				default:
 					if (Arrays.equals(option.getBasicStringListValue(), (String[])defaultValue)) {
 						return true;
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildDescription.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildDescription.java
index 0a4e5553f85..76cd98a6c00 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildDescription.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildDescription.java
@@ -1113,7 +1113,13 @@ public class BuildDescription implements IBuildDescription {
 								optType == IOption.INCLUDE_FILES ||
 								optType == IOption.LIBRARY_PATHS ||
 								optType == IOption.LIBRARY_FILES ||
-								optType == IOption.MACRO_FILES) {
+								optType == IOption.MACRO_FILES ||
+								optType == IOption.UNDEF_INCLUDE_PATH ||
+								optType == IOption.UNDEF_PREPROCESSOR_SYMBOLS ||
+								optType == IOption.UNDEF_INCLUDE_FILES ||
+								optType == IOption.UNDEF_LIBRARY_PATHS ||
+								optType == IOption.UNDEF_LIBRARY_FILES ||
+								optType == IOption.UNDEF_MACRO_FILES) {
 							List outputList = (List)option.getValue();
 							// Add outputPrefix to each if necessary
 							if(outputList != null && outputList.size() > 0){
@@ -1419,7 +1425,13 @@ public class BuildDescription implements IBuildDescription {
 								optType == IOption.INCLUDE_FILES ||
 								optType == IOption.LIBRARY_PATHS ||
 								optType == IOption.LIBRARY_FILES ||
-								optType == IOption.MACRO_FILES
+								optType == IOption.MACRO_FILES ||
+								optType == IOption.UNDEF_INCLUDE_PATH ||
+								optType == IOption.UNDEF_PREPROCESSOR_SYMBOLS ||
+								optType == IOption.UNDEF_INCLUDE_FILES ||
+								optType == IOption.UNDEF_LIBRARY_PATHS ||
+								optType == IOption.UNDEF_LIBRARY_FILES ||
+								optType == IOption.UNDEF_MACRO_FILES
 								) {
 							inputs = (List)option.getValue();
 						}
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildStep.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildStep.java
index 959da03b45b..077ed51e378 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildStep.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/buildmodel/BuildStep.java
@@ -573,7 +573,13 @@ public class BuildStep implements IBuildStep {
 							optType == IOption.INCLUDE_FILES ||
 							optType == IOption.LIBRARY_PATHS ||
 							optType == IOption.LIBRARY_FILES ||
-							optType == IOption.MACRO_FILES){
+							optType == IOption.MACRO_FILES ||
+							optType == IOption.UNDEF_INCLUDE_PATH ||
+							optType == IOption.UNDEF_PREPROCESSOR_SYMBOLS ||
+							optType == IOption.UNDEF_INCLUDE_FILES ||
+							optType == IOption.UNDEF_LIBRARY_PATHS ||
+							optType == IOption.UNDEF_LIBRARY_FILES ||
+							optType == IOption.UNDEF_MACRO_FILES){
 						//  Mote that when using the enumerated inputs, the path(s) must be translated from project relative 
 						//  to top build directory relative
 						String[] paths = new String[bRcs.length];
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/HoldsOptions.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/HoldsOptions.java
index c5d70db0ab2..79feda2a6d0 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/HoldsOptions.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/HoldsOptions.java
@@ -248,10 +248,17 @@ public abstract class HoldsOptions extends BuildObject implements IHoldsOptions,
 	 * @see org.eclipse.cdt.managedbuilder.core.IHoldsOptions#removeOption(IOption)
 	 */
 	public void removeOption(IOption option) {
+		if(option.getParent() != this)
+			throw new IllegalArgumentException();
+		
 		getOptionList().remove(option);
 		getOptionMap().remove(option.getId());
 		setDirty(true);
 		setRebuildState(true);
+		
+		if(!isExtensionElement()){
+			NotificationManager.getInstance().optionRemoved(getParentResourceInfo(), this, option);
+		}
 	}
 	
 	/* (non-Javadoc)
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ISettingsChangeListener.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ISettingsChangeListener.java
index 1dc239dd46d..d68104f155f 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ISettingsChangeListener.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ISettingsChangeListener.java
@@ -10,10 +10,7 @@
  *******************************************************************************/
 package org.eclipse.cdt.managedbuilder.internal.core;
 
-import org.eclipse.cdt.managedbuilder.core.IHoldsOptions;
-import org.eclipse.cdt.managedbuilder.core.IOption;
-import org.eclipse.cdt.managedbuilder.core.IResourceInfo;
 
 public interface ISettingsChangeListener {
-	void optionChanged(IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue);
+	void settingsChanged(SettingsChangeEvent event);
 }
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/NotificationManager.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/NotificationManager.java
index e9de8b2d062..948b06e846f 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/NotificationManager.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/NotificationManager.java
@@ -32,13 +32,31 @@ public class NotificationManager /*implements ISettingsChangeListener */{
 		return fInstance;
 	}
 
+	public void optionRemoved(IResourceInfo rcInfo, IHoldsOptions holder, IOption option) {
+		SettingsChangeEvent event = createOptionRemovedEvent(rcInfo, holder, option);
+		notifyListeners(event);
+	}
+
 	public void optionChanged(IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue) {
-		for(Iterator iter = fListeners.iterator(); iter.hasNext();){
-			ISettingsChangeListener listener = (ISettingsChangeListener)iter.next();
-			listener.optionChanged(rcInfo, holder, option, oldValue);
+		SettingsChangeEvent event = createOptionChangedEvent(rcInfo, holder, option, oldValue);
+		notifyListeners(event);
+	}
+	
+	private void notifyListeners(SettingsChangeEvent event){
+		ISettingsChangeListener listeners[] = (ISettingsChangeListener[])fListeners.toArray(new ISettingsChangeListener[fListeners.size()]); 
+		for(int i = 0; i < listeners.length; i++){
+			listeners[i].settingsChanged(event);
 		}
 	}
 	
+	private static SettingsChangeEvent createOptionChangedEvent(IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue){
+		return new SettingsChangeEvent(SettingsChangeEvent.CHANGED, rcInfo, holder, option, oldValue);
+	}
+
+	private static SettingsChangeEvent createOptionRemovedEvent(IResourceInfo rcInfo, IHoldsOptions holder, IOption option){
+		return new SettingsChangeEvent(SettingsChangeEvent.REMOVED, rcInfo, holder, option, null);
+	}
+
 	public void subscribe(ISettingsChangeListener listener){
 //		synchronized (this) {
 			fListeners.add(listener);
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Option.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Option.java
index 2cf4f355669..189805d1ec2 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Option.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Option.java
@@ -242,6 +242,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 					case LIBRARY_PATHS:
 					case LIBRARY_FILES:
 					case MACRO_FILES:
+					case UNDEF_INCLUDE_PATH:
+					case UNDEF_PREPROCESSOR_SYMBOLS:
+					case UNDEF_INCLUDE_FILES:
+					case UNDEF_LIBRARY_PATHS:
+					case UNDEF_LIBRARY_FILES:
+					case UNDEF_MACRO_FILES:
 						if (option.value != null) {
 							value = new ArrayList((ArrayList)option.value);
 						}
@@ -513,6 +519,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 				case LIBRARY_PATHS:
 				case LIBRARY_FILES:
 				case MACRO_FILES:
+				case UNDEF_INCLUDE_PATH:
+				case UNDEF_PREPROCESSOR_SYMBOLS:
+				case UNDEF_INCLUDE_FILES:
+				case UNDEF_LIBRARY_PATHS:
+				case UNDEF_LIBRARY_FILES:
+				case UNDEF_MACRO_FILES:
 					//  Note:  These string-list options do not load either the "value" or 
 					//         "defaultValue" attributes.  Instead, the ListOptionValue children
 					//         are loaded in the value field.
@@ -628,6 +640,18 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 			return INCLUDE_FILES;
 		else if (valueTypeStr.equals(TYPE_SYMBOL_FILES))
 			return MACRO_FILES;
+		else if (valueTypeStr.equals(TYPE_UNDEF_INC_PATH))
+			return UNDEF_INCLUDE_PATH;
+		else if (valueTypeStr.equals(TYPE_UNDEF_DEFINED_SYMBOLS))
+			return UNDEF_PREPROCESSOR_SYMBOLS;
+		else if (valueTypeStr.equals(TYPE_UNDEF_LIB_PATHS))
+			return UNDEF_LIBRARY_PATHS;
+		else if (valueTypeStr.equals(TYPE_UNDEF_LIB_FILES))
+			return UNDEF_LIBRARY_FILES;
+		else if (valueTypeStr.equals(TYPE_UNDEF_INC_FILES))
+			return UNDEF_INCLUDE_FILES;
+		else if (valueTypeStr.equals(TYPE_UNDEF_SYMBOL_FILES))
+			return UNDEF_MACRO_FILES;
 		else {
 			// TODO:  This was the CDT 2.0 default - should we keep it?
 			return PREPROCESSOR_SYMBOLS;
@@ -697,6 +721,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 				case LIBRARY_PATHS:
 				case LIBRARY_FILES:
 				case MACRO_FILES:
+				case UNDEF_INCLUDE_PATH:
+				case UNDEF_PREPROCESSOR_SYMBOLS:
+				case UNDEF_INCLUDE_FILES:
+				case UNDEF_LIBRARY_PATHS:
+				case UNDEF_LIBRARY_FILES:
+				case UNDEF_MACRO_FILES:
 					if (value != null) {
 						ArrayList stringList = (ArrayList)value;
 						ListIterator iter = stringList.listIterator();
@@ -774,6 +804,24 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 				case MACRO_FILES:
 					str = TYPE_SYMBOL_FILES;
 					break;
+				case UNDEF_INCLUDE_PATH:
+					str = TYPE_UNDEF_INC_PATH;
+					break;
+				case UNDEF_PREPROCESSOR_SYMBOLS:
+					str = TYPE_UNDEF_DEFINED_SYMBOLS;
+					break;
+				case UNDEF_INCLUDE_FILES:
+					str = TYPE_UNDEF_INC_FILES;
+					break;
+				case UNDEF_LIBRARY_PATHS:
+					str = TYPE_UNDEF_LIB_PATHS;
+					break;
+				case UNDEF_LIBRARY_FILES:
+					str = TYPE_UNDEF_LIB_FILES;
+					break;
+				case UNDEF_MACRO_FILES:
+					str = TYPE_UNDEF_SYMBOL_FILES;
+					break;
 				default:
 					//  TODO; is this a problem...
 					str = EMPTY_STRING; 
@@ -1335,6 +1383,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 					case LIBRARY_PATHS:
 					case LIBRARY_FILES:
 					case MACRO_FILES:
+					case UNDEF_INCLUDE_PATH:
+					case UNDEF_PREPROCESSOR_SYMBOLS:
+					case UNDEF_INCLUDE_FILES:
+					case UNDEF_LIBRARY_PATHS:
+					case UNDEF_LIBRARY_FILES:
+					case UNDEF_MACRO_FILES:
 						val = new ArrayList();
 						break;
 					default:
@@ -1516,6 +1570,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 			|| getValueType() == LIBRARY_PATHS
 			|| getValueType() == LIBRARY_FILES
 			|| getValueType() == MACRO_FILES
+			|| getValueType() == UNDEF_INCLUDE_PATH
+			|| getValueType() == UNDEF_PREPROCESSOR_SYMBOLS
+			|| getValueType() == UNDEF_INCLUDE_FILES
+			|| getValueType() == UNDEF_LIBRARY_PATHS
+			|| getValueType() == UNDEF_LIBRARY_FILES
+			|| getValueType() == UNDEF_MACRO_FILES
 			  )) {
 			// Just replace what the option reference is holding onto
 			if(value == null)
@@ -1773,6 +1833,12 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 					case LIBRARY_PATHS:
 					case LIBRARY_FILES:
 					case MACRO_FILES:
+					case UNDEF_INCLUDE_PATH:
+					case UNDEF_PREPROCESSOR_SYMBOLS:
+					case UNDEF_INCLUDE_FILES:
+					case UNDEF_LIBRARY_PATHS:
+					case UNDEF_LIBRARY_FILES:
+					case UNDEF_MACRO_FILES:
 						//  Note:  These string-list options do not load either the "value" or 
 						//         "defaultValue" attributes.  Instead, the ListOptionValue children
 						//         are loaded in the value field.
@@ -2064,4 +2130,34 @@ public class Option extends BuildObject implements IOption, IBuildPropertiesRest
 		
 		return false;
 	}
+	
+	public static int getOppositeType(int type){
+		switch(type){
+		case INCLUDE_PATH:
+			return UNDEF_INCLUDE_PATH;
+		case PREPROCESSOR_SYMBOLS:
+			return UNDEF_PREPROCESSOR_SYMBOLS;
+		case INCLUDE_FILES:
+			return UNDEF_INCLUDE_FILES;
+		case LIBRARY_PATHS:
+			return UNDEF_LIBRARY_PATHS;
+		case LIBRARY_FILES:
+			return UNDEF_LIBRARY_FILES;
+		case MACRO_FILES:
+			return UNDEF_MACRO_FILES;
+		case UNDEF_INCLUDE_PATH:
+			return INCLUDE_PATH;
+		case UNDEF_PREPROCESSOR_SYMBOLS:
+			return PREPROCESSOR_SYMBOLS;
+		case UNDEF_INCLUDE_FILES:
+			return INCLUDE_FILES;
+		case UNDEF_LIBRARY_PATHS:
+			return LIBRARY_PATHS;
+		case UNDEF_LIBRARY_FILES:
+			return LIBRARY_FILES;
+		case UNDEF_MACRO_FILES:
+			return MACRO_FILES;
+		}
+		return 0;
+	}
 }
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/OptionReference.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/OptionReference.java
index 94517f029ba..75157e02142 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/OptionReference.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/OptionReference.java
@@ -137,7 +137,12 @@ public class OptionReference implements IOption {
 			case LIBRARY_PATHS:
 			case LIBRARY_FILES:
 			case MACRO_FILES:
-
+			case UNDEF_INCLUDE_PATH:
+			case UNDEF_PREPROCESSOR_SYMBOLS:
+			case UNDEF_INCLUDE_FILES:
+			case UNDEF_LIBRARY_PATHS:
+			case UNDEF_LIBRARY_FILES:
+			case UNDEF_MACRO_FILES:
 				List valueList = new ArrayList();
 				NodeList nodes = element.getElementsByTagName(LIST_VALUE);
 				for (int i = 0; i < nodes.getLength(); ++i) {
@@ -205,6 +210,12 @@ public class OptionReference implements IOption {
 				case LIBRARY_PATHS:
 				case LIBRARY_FILES:
 				case MACRO_FILES:
+				case UNDEF_INCLUDE_PATH:
+				case UNDEF_PREPROCESSOR_SYMBOLS:
+				case UNDEF_INCLUDE_FILES:
+				case UNDEF_LIBRARY_PATHS:
+				case UNDEF_LIBRARY_FILES:
+				case UNDEF_MACRO_FILES:
 					List valueList = new ArrayList();
 					IManagedConfigElement[] valueElements = element.getChildren(LIST_VALUE);
 					for (int i = 0; i < valueElements.length; ++i) {
@@ -258,6 +269,12 @@ public class OptionReference implements IOption {
 			case LIBRARY_PATHS:
 			case LIBRARY_FILES:
 			case MACRO_FILES:
+			case UNDEF_INCLUDE_PATH:
+			case UNDEF_PREPROCESSOR_SYMBOLS:
+			case UNDEF_INCLUDE_FILES:
+			case UNDEF_LIBRARY_PATHS:
+			case UNDEF_LIBRARY_FILES:
+			case UNDEF_MACRO_FILES:
 				ArrayList stringList = (ArrayList)value;
 				ListIterator iter = stringList.listIterator();
 				while (iter.hasNext()) {
@@ -651,7 +668,14 @@ public class OptionReference implements IOption {
 			|| getValueType() == INCLUDE_FILES
 			|| getValueType() == LIBRARY_PATHS
 			|| getValueType() == LIBRARY_FILES
-			|| getValueType() == MACRO_FILES) {
+			|| getValueType() == MACRO_FILES
+			|| getValueType() == UNDEF_INCLUDE_PATH
+			|| getValueType() == UNDEF_PREPROCESSOR_SYMBOLS
+			|| getValueType() == UNDEF_INCLUDE_FILES
+			|| getValueType() == UNDEF_LIBRARY_PATHS
+			|| getValueType() == UNDEF_LIBRARY_FILES
+			|| getValueType() == UNDEF_MACRO_FILES
+			) {
 			// Just replace what the option reference is holding onto 
 			this.value = new ArrayList(Arrays.asList(value));
 		}
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/SettingsChangeEvent.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/SettingsChangeEvent.java
new file mode 100644
index 00000000000..e08a3c7fa35
--- /dev/null
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/SettingsChangeEvent.java
@@ -0,0 +1,63 @@
+/*******************************************************************************
+ * Copyright (c) 2007 Intel Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * Intel Corporation - Initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.managedbuilder.internal.core;
+
+import org.eclipse.cdt.managedbuilder.core.IHoldsOptions;
+import org.eclipse.cdt.managedbuilder.core.IOption;
+import org.eclipse.cdt.managedbuilder.core.IResourceInfo;
+
+public class SettingsChangeEvent {
+	private IResourceInfo fRcInfo;
+	private IHoldsOptions fHolder;
+	private IOption fOption;
+	private Object fOldValue;
+	
+	private int fChangeType;
+	private int fSettingType;
+	public static final int CHANGED = 1;
+	public static final int ADDED = 1 << 1;
+	public static final int REMOVED = 1 << 2;
+	
+	public static final int OPTION = 1;
+	
+	SettingsChangeEvent(int changeType, IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue){
+		fSettingType = OPTION;
+		fChangeType = changeType;
+		fRcInfo = rcInfo;
+		fHolder = holder;
+		fOption = option;
+		fOldValue = oldValue;
+	}
+
+	public IResourceInfo getRcInfo() {
+		return fRcInfo;
+	}
+
+	public IHoldsOptions getHolder() {
+		return fHolder;
+	}
+
+	public IOption getOption() {
+		return fOption;
+	}
+
+	public Object getOldValue() {
+		return fOldValue;
+	}
+
+	public int getChangeType() {
+		return fChangeType;
+	}
+
+	public int getSettingType() {
+		return fSettingType;
+	}
+}
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
index 6f9763f5103..700008a6320 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
@@ -53,7 +53,9 @@ import org.eclipse.cdt.managedbuilder.core.IResourceInfo;
 import org.eclipse.cdt.managedbuilder.core.ITool;
 import org.eclipse.cdt.managedbuilder.core.IToolChain;
 import org.eclipse.cdt.managedbuilder.core.ManagedBuildManager;
+import org.eclipse.cdt.managedbuilder.core.ManagedBuilderCorePlugin;
 import org.eclipse.cdt.managedbuilder.internal.dataprovider.BuildLanguageData;
+import org.eclipse.cdt.managedbuilder.internal.dataprovider.EntryStorage;
 import org.eclipse.cdt.managedbuilder.internal.enablement.OptionEnablementExpression;
 import org.eclipse.cdt.managedbuilder.internal.macros.BuildMacroProvider;
 import org.eclipse.cdt.managedbuilder.internal.macros.BuildfileMacroSubstitutor;
@@ -79,6 +81,8 @@ import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.core.runtime.content.IContentTypeSettings;
 import org.eclipse.core.runtime.preferences.IScopeContext;
 
+import com.sun.rsasign.l;
+
 /**
  * Represents a tool that can be invoked during a build.
  * Note that this class implements IOptionCategory to represent the top
@@ -1903,9 +1907,12 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 									optType == IOption.INCLUDE_FILES ||
 									optType == IOption.LIBRARY_PATHS ||
 									optType == IOption.LIBRARY_FILES ||
-									optType == IOption.MACRO_FILES) {
+									optType == IOption.MACRO_FILES
+									) {
 								List inputNames = (List)option.getValue();
+								filterValues(optType, inputNames);
 								for (int j=0; j<inputNames.size(); j++) {
+									
 									inputs.add(Path.fromOSString((String)inputNames.get(j)));
 								}
 							}
@@ -2581,7 +2588,10 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 				case IOption.LIBRARY_PATHS :
 				case IOption.LIBRARY_FILES :
 				case IOption.MACRO_FILES :
-				{
+				case IOption.UNDEF_INCLUDE_FILES :
+				case IOption.UNDEF_LIBRARY_PATHS :
+				case IOption.UNDEF_LIBRARY_FILES :
+				case IOption.UNDEF_MACRO_FILES :				{
 						String listCmd = option.getCommand();
 						IMacroContextInfo info = provider.getMacroContextInfo(IBuildMacroProvider.CONTEXT_FILE,
 								new FileContextData(inputFileLocation, outputFileLocation, option, this));
@@ -2599,7 +2609,8 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 					}
 					break;
 					
-				case IOption.INCLUDE_PATH :{
+				case IOption.INCLUDE_PATH :
+				case IOption.UNDEF_INCLUDE_PATH :{
 					String incCmd = option.getCommand();
 					IMacroContextInfo info = provider.getMacroContextInfo(IBuildMacroProvider.CONTEXT_FILE,
 							new FileContextData(inputFileLocation, outputFileLocation, option, this));
@@ -2617,7 +2628,8 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 				}
 					break;
 	
-				case IOption.PREPROCESSOR_SYMBOLS :{
+				case IOption.PREPROCESSOR_SYMBOLS :
+				case IOption.UNDEF_PREPROCESSOR_SYMBOLS :{
 					String defCmd = option.getCommand();
 					IMacroContextInfo info = provider.getMacroContextInfo(IBuildMacroProvider.CONTEXT_FILE,
 							new FileContextData(inputFileLocation, outputFileLocation, option, this));
@@ -4024,4 +4036,47 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 		//scannerConfigDiscoveryProfileId
 		return false;
 	}
+	
+	public IOption[] getOptionsOfType(int type){
+		IOption options[] = getOptions();
+		List list = new ArrayList();
+		for(int i = 0; i < options.length; i++){
+			try {
+				if(options[i].getValueType() == type){
+					list.add(options[i]);
+				}
+			} catch (BuildException e) {
+				ManagedBuilderCorePlugin.log(e);
+			}
+		}
+		return (Option[])list.toArray(new Option[list.size()]);
+	}
+	
+	public void filterValues(int type, List values){
+		if(values.size() == 0)
+			return;
+		
+		int opType = Option.getOppositeType(type);
+		if(opType != 0){
+			IOption opOptions[] = getOptionsOfType(opType);
+			Set filterSet = new HashSet();
+			for(int i = 0; i < opOptions.length; i++){
+				List opList = (List)opOptions[i].getValue();
+				filterSet.addAll(opList);
+			}
+			
+			if(filterSet.size() != 0){
+				Object oVal;
+				for(int i = 0; i < values.size(); i++){
+					oVal = values.get(i);
+					if(type == IOption.PREPROCESSOR_SYMBOLS){
+						String[] nameVal = EntryStorage.macroNameValueFromValue((String)oVal);
+						oVal = nameVal[0];
+					}
+					if(filterSet.contains(oVal))
+						values.remove(i);
+				}
+			}
+		}
+	}
 }
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/BuildLanguageData.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/BuildLanguageData.java
index 2fc89115dc4..fabb157ded8 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/BuildLanguageData.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/BuildLanguageData.java
@@ -36,6 +36,7 @@ public class BuildLanguageData extends CLanguageData {
 	private ITool fTool;
 	private IInputType fInputType;
 	private KindBasedStore fKindToOptionArrayStore = new KindBasedStore();
+	private KindBasedStore fKindToUndefOptionArrayStore = new KindBasedStore();
 	private static final IOption[] EMPTY_OPTION_ARRAY = new IOption[0];
 	private boolean fOptionStoreInited;
 //	private Map fKindToEntryArrayMap = new HashMap();
@@ -95,20 +96,20 @@ public class BuildLanguageData extends CLanguageData {
 		return starage;
 	}
 	
-	private void optionsChanged(int kind, IOption option, Object oldValue){
+	private void notifyOptionsChangeForKind(int kind){
 		fOptionStoreInited = false;
 		EntryStorage storage = getEntryStorage(kind);
 		if(storage != null)
-			storage.optionsChanged(option, oldValue);
+			storage.optionsChanged();
 	}
 	
-	public void optionChanged(IOption option, Object oldValue){
-		try {
-			int kind = ManagedBuildManager.optionTypeToEntryKind(option.getValueType());
-			if(kind != 0)
-				optionsChanged(kind, option, oldValue);
-		} catch (BuildException e) {
-		}
+	public void optionsChanged(int type){
+		int kind = ManagedBuildManager.optionTypeToEntryKind(type);
+		if(kind == 0)
+			kind = ManagedBuildManager.optionUndefTypeToEntryKind(type);
+		
+		if(kind != 0)
+			notifyOptionsChangeForKind(kind);
 	}
 	
 	private ProfileInfoProvider getDiscoveredInfoProvider(){
@@ -306,12 +307,23 @@ public class BuildLanguageData extends CLanguageData {
 	}
 	
 	private KindBasedStore getKindToOptionArrayStore(){
-		if(!fOptionStoreInited){
-			calculateKindToOptionArrayStore();
-			fOptionStoreInited = true;
-		}
+		initOptionStores();
 		return fKindToOptionArrayStore;
 	}
+
+	private void initOptionStores(){
+		if(!fOptionStoreInited){
+			calculateKindToOptionArrayStore();
+			calculateKindToUndefOptionArrayStore();
+			fOptionStoreInited = true;
+		}
+	}
+
+	private KindBasedStore getKindToUndefOptionArrayStore(){
+		initOptionStores();
+		return fKindToUndefOptionArrayStore;
+	}
+
 	private void calculateKindToOptionArrayStore(){
 		fKindToOptionArrayStore.clear();
 		IOption options[] = fTool.getOptions();
@@ -340,6 +352,41 @@ public class BuildLanguageData extends CLanguageData {
 			}
 		}
 	}
+	
+	private void calculateKindToUndefOptionArrayStore(){
+		fKindToUndefOptionArrayStore.clear();
+		IOption options[] = fTool.getOptions();
+		for(int i = 0; i < options.length; i++){
+			IOption option = options[i];
+			try {
+				int type = option.getValueType();
+				int entryKind = ManagedBuildManager.optionUndefTypeToEntryKind(type);
+				if(entryKind != 0){
+					getOptionList(fKindToUndefOptionArrayStore, entryKind).add(option);
+				}
+			} catch (BuildException e) {
+			}
+		}
+		
+		IKindBasedInfo infos[] = fKindToUndefOptionArrayStore.getContents();
+		IKindBasedInfo info;
+		for(int i = 0; i < infos.length; i++){
+			info = infos[i];
+			List list = (List)info.getInfo();
+			if(list != null){
+				IOption[] opts = (IOption[])list.toArray(new IOption[list.size()]);
+				info.setInfo(opts);
+			} else {
+				info.setInfo(EMPTY_OPTION_ARRAY);
+			}
+		}
+	}
+
+
+	IOption[] getUndefOptionsForKind(int entryKind){
+		KindBasedStore store = getKindToUndefOptionArrayStore();
+		return (IOption[])store.get(entryKind);
+	}
 
 	IOption[] getOptionsForKind(int entryKind){
 		KindBasedStore store = getKindToOptionArrayStore();
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ConfigurationDataProvider.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ConfigurationDataProvider.java
index 0870cb4dfcf..f63d8c45631 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ConfigurationDataProvider.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ConfigurationDataProvider.java
@@ -26,9 +26,9 @@ import org.eclipse.cdt.core.settings.model.ICProjectDescription;
 import org.eclipse.cdt.core.settings.model.ICStorageElement;
 import org.eclipse.cdt.core.settings.model.extension.CConfigurationData;
 import org.eclipse.cdt.core.settings.model.extension.CConfigurationDataProvider;
+import org.eclipse.cdt.managedbuilder.core.BuildException;
 import org.eclipse.cdt.managedbuilder.core.IConfiguration;
 import org.eclipse.cdt.managedbuilder.core.IFolderInfo;
-import org.eclipse.cdt.managedbuilder.core.IHoldsOptions;
 import org.eclipse.cdt.managedbuilder.core.IInputType;
 import org.eclipse.cdt.managedbuilder.core.IManagedBuildInfo;
 import org.eclipse.cdt.managedbuilder.core.IManagedOptionValueHandler;
@@ -45,6 +45,7 @@ import org.eclipse.cdt.managedbuilder.internal.core.InputType;
 import org.eclipse.cdt.managedbuilder.internal.core.ManagedBuildInfo;
 import org.eclipse.cdt.managedbuilder.internal.core.ManagedProject;
 import org.eclipse.cdt.managedbuilder.internal.core.NotificationManager;
+import org.eclipse.cdt.managedbuilder.internal.core.SettingsChangeEvent;
 import org.eclipse.cdt.managedbuilder.internal.core.Tool;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.CoreException;
@@ -420,14 +421,20 @@ public class ConfigurationDataProvider extends CConfigurationDataProvider implem
 		return cfgDes.getSessionProperty(CFG_PERSISTED_PROPERTY) != null;
 	}
 
-	public void optionChanged(IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue) {
-		BuildLanguageData datas[] = (BuildLanguageData[])rcInfo.getCLanguageDatas();
-		for(int i = 0; i < datas.length; i++){
-			datas[i].optionChanged(option, oldValue);
+	public void settingsChanged(SettingsChangeEvent event) {
+		BuildLanguageData datas[] = (BuildLanguageData[])event.getRcInfo().getCLanguageDatas();
+		IOption option = event.getOption();
+		
+		try {
+			int type = option.getValueType();
+			for(int i = 0; i < datas.length; i++){
+				datas[i].optionsChanged(type);
+			}
+		} catch (BuildException e) {
+			ManagedBuilderCorePlugin.log(e);
 		}
 	}
 
-
 	public void removeConfiguration(ICConfigurationDescription des,
 			CConfigurationData data,
 			IProgressMonitor monitor) {
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/EntryStorage.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/EntryStorage.java
index 901a98f55f9..95f10231f26 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/EntryStorage.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/EntryStorage.java
@@ -12,7 +12,9 @@ package org.eclipse.cdt.managedbuilder.internal.dataprovider;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import org.eclipse.cdt.core.settings.model.CIncludeFileEntry;
 import org.eclipse.cdt.core.settings.model.CIncludePathEntry;
@@ -54,7 +56,7 @@ public class EntryStorage {
 		return fKind;
 	}
 	
-	void optionsChanged(IOption option, Object oldValue){
+	void optionsChanged(){
 		fUserValuesInited = false;
 	}
 	
@@ -89,6 +91,14 @@ public class EntryStorage {
 				tool.removeOption(option);
 			}
 		}
+		
+		options = fLangData.getUndefOptionsForKind(fKind);
+		for(int i = 0; i < options.length; i++){
+			IOption option = options[i];
+			if(option.getParent() == tool){
+				tool.removeOption(option);
+			}
+		}
 	}
 	
 	private void resetCache(){
@@ -126,22 +136,42 @@ public class EntryStorage {
 		
 		SettingLevel level = fSettings.getLevels()[0];
 		ICLanguageSettingEntry usrEntries[] = level.getEntries();
-		IOption options[] = fLangData.getOptionsForKind(fKind);
-		if(options.length > 0){
-			IOption option = options[0];
-			String optValue[] = new String[usrEntries.length]; 
-			for(int i = 0; i < usrEntries.length; i++){
-				ICLanguageSettingEntry entry = usrEntries[i];
-				optValue[i] = entryValueToOption(entry);
+		if(usrEntries.length != 0){
+			IOption options[] = fLangData.getOptionsForKind(fKind);
+			if(options.length > 0){
+				IOption option = options[0];
+				String optValue[] = new String[usrEntries.length]; 
+				for(int i = 0; i < usrEntries.length; i++){
+					ICLanguageSettingEntry entry = usrEntries[i];
+					optValue[i] = entryValueToOption(entry);
+				}
+				
+				ITool tool = fLangData.getTool();
+				IResourceInfo rcInfo = tool.getParentResourceInfo();
+				IOption newOption = ManagedBuildManager.setOption(rcInfo, tool, option, optValue);
+				options = fLangData.getOptionsForKind(fKind);
+				for(int i = 0; i < options.length; i++){
+					if(options[i] != newOption)
+						ManagedBuildManager.setOption(rcInfo, tool, option, new String[0]);
+				}
 			}
-			
-			ITool tool = fLangData.getTool();
-			IResourceInfo rcInfo = tool.getParentResourceInfo();
-			IOption newOption = ManagedBuildManager.setOption(rcInfo, tool, option, optValue);
-			options = fLangData.getOptionsForKind(fKind);
-			for(int i = 0; i < options.length; i++){
-				if(options[i] != newOption)
-					ManagedBuildManager.setOption(rcInfo, tool, option, new String[0]);
+		}
+		
+		if(level.containsOverrideInfo()){
+			IOption options[] = fLangData.getUndefOptionsForKind(fKind);
+			if(options.length != 0){
+				Set set = level.getOverrideSet();
+				IOption option = options[0];
+				String[] optValue = (String[])set.toArray(new String[set.size()]);
+				
+				ITool tool = fLangData.getTool();
+				IResourceInfo rcInfo = tool.getParentResourceInfo();
+				IOption newOption = ManagedBuildManager.setOption(rcInfo, tool, option, optValue);
+				options = fLangData.getUndefOptionsForKind(fKind);
+				for(int i = 0; i < options.length; i++){
+					if(options[i] != newOption)
+						ManagedBuildManager.setOption(rcInfo, tool, option, new String[0]);
+				}
 			}
 		}
 	}
@@ -169,6 +199,7 @@ public class EntryStorage {
 			
 			dEntries = getUserDiscoveredEntries();
 			addEntries(levels[0], dEntries);
+			levels[0].fOverrideSet = getUserUndefinedStringSet(); 
 			
 			fSettings.adjustOverrideState();
 ////			fDiscoveredEntries.clear();
@@ -228,28 +259,37 @@ public class EntryStorage {
 		SettingsSet settings = new SettingsSet(3);
 		SettingLevel levels[] = settings.getLevels();
 		
+		boolean override = isDiscoveredEntriesOverridable(); 
+		int readOnlyFlag = override ? 0 : ICSettingEntry.READONLY;
 		levels[0].setFlagsToClear(ICSettingEntry.READONLY | ICSettingEntry.BUILTIN);
 		levels[0].setFlagsToSet(0);
 		levels[0].setReadOnly(false);
+		levels[0].setOverrideSupported(override);
 
 		levels[1].setFlagsToClear(ICSettingEntry.BUILTIN);
-		levels[1].setFlagsToSet(ICSettingEntry.READONLY | ICSettingEntry.RESOLVED);
+		levels[1].setFlagsToSet(readOnlyFlag | ICSettingEntry.RESOLVED);
 		levels[1].setReadOnly(true);
+		levels[1].setOverrideSupported(false);
 
 		levels[2].setFlagsToClear(0);
-		levels[2].setFlagsToSet(ICSettingEntry.READONLY | ICSettingEntry.BUILTIN | ICSettingEntry.RESOLVED);
+		levels[2].setFlagsToSet(readOnlyFlag | ICSettingEntry.BUILTIN | ICSettingEntry.RESOLVED);
 		levels[2].setReadOnly(true);
+		levels[2].setOverrideSupported(false);
 
 		return settings;
 	}
 	
-	private boolean isDiscoveredEntriesReadOnly(){
-		if(fKind == ICLanguageSettingEntry.MACRO){
-			return fLangData.getOptionsForKind(fKind).length != 0;
-		}
-		return true;
+	private boolean isDiscoveredEntriesOverridable(){
+//		if(!needUndef())
+//			return false;
+		
+		return fLangData.getUndefOptionsForKind(fKind).length != 0;
 	}
 	
+//	private boolean needUndef(){
+//		return fKind != ICLanguageSettingEntry.MACRO;
+//	}
+	
 //	private void initUserValues(){
 //		IOption options[] = fLangData.getOptionsForKind(fKind);
 //		fUserEntries.clear();
@@ -279,6 +319,22 @@ public class EntryStorage {
 //		}
 //	}
 	
+	private HashSet getUserUndefinedStringSet(){
+		HashSet set = null;
+		IOption options[] = fLangData.getUndefOptionsForKind(fKind);
+		if(options.length > 0){
+			for(int i = 0; i < options.length; i++){
+				IOption option = options[i];
+				List list = (List)option.getValue();
+				if(list.size() != 0){
+					if(set == null)
+						set = new HashSet();
+					set.addAll(list);
+				}
+			}
+		}
+		return set;
+	}
 	private DiscoveredEntry[] getUserDiscoveredEntries(){
 		IOption options[] = fLangData.getOptionsForKind(fKind);
 		if(options.length > 0){
@@ -403,7 +459,7 @@ public class EntryStorage {
 		
 	}
 
-	private String[] macroNameValueFromValue(String value){
+	public static String[] macroNameValueFromValue(String value){
 		String nv[] = new String[2];
 		int index = value.indexOf('=');
 		if(index > 0){
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/SettingsSet.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/SettingsSet.java
index 74ebc1faadd..fd78666e92c 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/SettingsSet.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/SettingsSet.java
@@ -13,6 +13,7 @@ package org.eclipse.cdt.managedbuilder.internal.dataprovider;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -30,7 +31,9 @@ public class SettingsSet {
 		private int fFlagsToSet;
 		private int fFlagsToClear;
 		private boolean fIsReadOnly;
+		private boolean fIsOverrideSupported;
 		private EntryListMap fEntries;
+		HashSet fOverrideSet;
 		
 		private SettingLevel(){
 			fEntries = new EntryListMap();
@@ -43,10 +46,22 @@ public class SettingsSet {
 		public void setReadOnly(boolean readOnly){
 			fIsReadOnly = readOnly;
 		}
+
+		public boolean isOverrideSupported(){
+			return fIsOverrideSupported;
+		}
 		
+		public void setOverrideSupported(boolean supported){
+			fIsOverrideSupported = supported;
+		}
+
 		public void setFlagsToSet(int flags){
 			fFlagsToSet = flags;
 		}
+		
+		public boolean containsOverrideInfo(){
+			return fOverrideSet != null;
+		}
 
 		public void setFlagsToClear(int flags){
 			fFlagsToClear = flags;
@@ -60,13 +75,37 @@ public class SettingsSet {
 			return fFlagsToClear;
 		}
 		
+		public Set getOverrideSet(){
+			if(fOverrideSet != null)
+				return (HashSet)fOverrideSet.clone();
+			return new HashSet();
+		}
+		
 		public void addEntry(ICLanguageSettingEntry entry){
 			entry = CDataUtil.createEntry(entry, fFlagsToSet, fFlagsToClear);
 			fEntries.addEntryInfo(new EntryInfo(entry));
 		}
 		
+		public void addOverrideName(String name){
+			if(fOverrideSet == null)
+				fOverrideSet = new HashSet();
+			
+			fOverrideSet.add(name);
+		}
+
+		public void removeOverrideName(String name){
+			if(fOverrideSet == null)
+				return;
+			
+			fOverrideSet.remove(name);
+			
+			if(fOverrideSet.size() == 0)
+				fOverrideSet = null;
+		}
+
 		public void clear(){
 			fEntries.clear();
+			fOverrideSet = null;
 		}
 		
 		EntryInfo[] getInfos(){
@@ -83,8 +122,6 @@ public class SettingsSet {
 			
 			return (ICLanguageSettingEntry[])list.toArray(new ICLanguageSettingEntry[list.size()]);
 		}
-		
-		
 	}
 	
 	public SettingsSet(int num){
@@ -99,7 +136,11 @@ public class SettingsSet {
 	}
 	
 	public void adjustOverrideState(){
-		Set set = new HashSet();
+		int dNum = getDefaultLevelNum();
+		SettingLevel dLevel = fLevels[dNum];
+		
+		
+		Set set = dLevel.isOverrideSupported() ? dLevel.getOverrideSet() : new HashSet();
 		for(int i = 0; i < fLevels.length; i++){
 			adjustOverrideState(fLevels[i], set);
 		}
@@ -110,7 +151,7 @@ public class SettingsSet {
 		EntryInfo info;
 		for(int i = 0; i < infos.length; i++){
 			info = infos[i];
-			if(overridenSet.add(info.getNameKey())){
+			if(overridenSet.add(info.getEntry().getName())){
 				info.makeOverridden(false);
 			} else {
 				info.makeOverridden(true);
@@ -162,7 +203,8 @@ public class SettingsSet {
 	}
 
 	public void applyEntries(ICLanguageSettingEntry[] entries){
-		Map map = getEntryLevelMap(WRITABLE | READ_ONLY);
+		HashMap map = getEntryLevelMap(WRITABLE | READ_ONLY);
+		Map mapCopy = (HashMap)map.clone();
 		
 		for(int i = 0; i < fLevels.length; i++){
 			if(!fLevels[i].isReadOnly()){
@@ -180,18 +222,35 @@ public class SettingsSet {
 		for(int i = 0; i < entries.length; i++){
 			entry = entries[i];
 			key = new EntryNameKey(entry);
-			levelInteger = (Integer)map.get(key);
+			Object[] o = (Object[])map.get(key);
+
+			if(o != null){
+				mapCopy.remove(key);
+				levelInteger = (Integer)o[0]; 
+			} else {
+				levelInteger = null;
+			}
+
 			levelNum = levelInteger != null ? levelInteger.intValue() : defaultLevel;
 			level = fLevels[levelNum];
 			if(!level.isReadOnly())
 				level.addEntry(entry);
 		}
 		
+		level = fLevels[defaultLevel];
+		if(level.isOverrideSupported() && !mapCopy.isEmpty()){
+			String str;
+			for(Iterator iter = mapCopy.keySet().iterator(); iter.hasNext();){
+				str = ((EntryNameKey)iter.next()).getEntry().getName();
+				if(str != null)
+					level.addOverrideName(str);
+			}
+		}
 		adjustOverrideState();
 	}
 	
-	public Map getEntryLevelMap(int types){
-		Map map = new HashMap();
+	public HashMap getEntryLevelMap(int types){
+		HashMap map = new HashMap();
 		for(int i = 0; i < fLevels.length; i++){
 			if(isCompatible(fLevels[i], types))
 				addLevelInfoToMap(fLevels[i], i, map);
@@ -209,7 +268,7 @@ public class SettingsSet {
 			info = infos[i];
 			key = info.getNameKey(); 
 			if(!map.containsKey(key))
-				map.put(key, new Integer(l));
+				map.put(key, new Object[]{new Integer(l), info.getEntry()});
 		}
 	}
 }
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/CheckOptionExpression.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/CheckOptionExpression.java
index eb1d445e1f4..ae852ee6a96 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/CheckOptionExpression.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/CheckOptionExpression.java
@@ -116,7 +116,13 @@ public class CheckOptionExpression implements IBooleanExpression {
 				case IOption.INCLUDE_FILES:
 				case IOption.LIBRARY_PATHS:
 				case IOption.LIBRARY_FILES:
-				case IOption.MACRO_FILES:{
+				case IOption.MACRO_FILES:
+				case IOption.UNDEF_INCLUDE_PATH:
+				case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+				case IOption.UNDEF_INCLUDE_FILES:
+				case IOption.UNDEF_LIBRARY_PATHS:
+				case IOption.UNDEF_LIBRARY_FILES:
+				case IOption.UNDEF_MACRO_FILES:{
 					List list = (List)option.getValue();
 					String listValue = provider.convertStringListToString((String[])list.toArray(new String[list.size()]),delimiter);
 
@@ -175,7 +181,13 @@ public class CheckOptionExpression implements IBooleanExpression {
 				case IOption.INCLUDE_FILES:
 				case IOption.LIBRARY_PATHS:
 				case IOption.LIBRARY_FILES:
-				case IOption.MACRO_FILES:{
+				case IOption.MACRO_FILES:
+				case IOption.UNDEF_INCLUDE_PATH:
+				case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+				case IOption.UNDEF_INCLUDE_FILES:
+				case IOption.UNDEF_LIBRARY_PATHS:
+				case IOption.UNDEF_LIBRARY_FILES:
+				case IOption.UNDEF_MACRO_FILES:{
 					List list = (List)option.getValue();
 					String listValue[] = (String[])list.toArray(new String[list.size()]);
 					
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/OptionEnablementExpression.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/OptionEnablementExpression.java
index fdf46a054ea..48d9bf91bd2 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/OptionEnablementExpression.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/enablement/OptionEnablementExpression.java
@@ -313,6 +313,12 @@ public class OptionEnablementExpression extends AndExpression{
 				case IOption.LIBRARY_PATHS:
 				case IOption.LIBRARY_FILES:
 				case IOption.MACRO_FILES:
+				case IOption.UNDEF_INCLUDE_PATH:
+				case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+				case IOption.UNDEF_INCLUDE_FILES:
+				case IOption.UNDEF_LIBRARY_PATHS:
+				case IOption.UNDEF_LIBRARY_FILES:
+				case IOption.UNDEF_MACRO_FILES:
 					//TODO: add String list value support
 					adjusted = false;
 					break;
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/macros/MbsMacroSupplier.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/macros/MbsMacroSupplier.java
index 69748aa35ed..19b21a944e2 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/macros/MbsMacroSupplier.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/macros/MbsMacroSupplier.java
@@ -923,6 +923,30 @@ public class MbsMacroSupplier extends BuildCdtVariablesSupplierBase {
 						fType = IBuildMacro.VALUE_PATH_FILE_LIST;
 						fStringListValue = option.getBasicStringListValue();
 						break;
+					case IOption.UNDEF_INCLUDE_PATH:
+						fType = IBuildMacro.VALUE_PATH_DIR_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
+					case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+						fType = IBuildMacro.VALUE_TEXT_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
+					case IOption.UNDEF_INCLUDE_FILES:
+						fType = IBuildMacro.VALUE_PATH_FILE_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
+					case IOption.UNDEF_LIBRARY_PATHS:
+						fType = IBuildMacro.VALUE_PATH_DIR_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
+					case IOption.UNDEF_LIBRARY_FILES:
+						fType = IBuildMacro.VALUE_PATH_FILE_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
+					case IOption.UNDEF_MACRO_FILES:
+						fType = IBuildMacro.VALUE_PATH_FILE_LIST;
+						fStringListValue = option.getBasicStringListValue();
+						break;
 					}
 					if(fStringValue != null)
 						fStringValue = CdtVariableResolver.resolveToString(fStringValue,new IncludeDefaultsSubstitutor(fParentOptionContextData));
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/GnuMakefileGenerator.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/GnuMakefileGenerator.java
index 244f59f6c6a..c5ef08ba222 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/GnuMakefileGenerator.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/GnuMakefileGenerator.java
@@ -51,7 +51,7 @@ import org.eclipse.cdt.managedbuilder.core.ITool;
 import org.eclipse.cdt.managedbuilder.core.ManagedBuildManager;
 import org.eclipse.cdt.managedbuilder.core.ManagedBuilderCorePlugin;
 import org.eclipse.cdt.managedbuilder.internal.core.ManagedMakeMessages;
-import org.eclipse.cdt.managedbuilder.internal.core.ResourceInfo;
+import org.eclipse.cdt.managedbuilder.internal.core.Tool;
 import org.eclipse.cdt.managedbuilder.internal.macros.BuildMacroProvider;
 import org.eclipse.cdt.managedbuilder.internal.macros.FileContextData;
 import org.eclipse.cdt.managedbuilder.macros.BuildMacroException;
@@ -2975,6 +2975,7 @@ public class GnuMakefileGenerator implements IManagedBuilderMakefileGenerator2 {
 									optType == IOption.LIBRARY_PATHS ||
 									optType == IOption.LIBRARY_FILES ||
 									optType == IOption.MACRO_FILES) {
+								//TODO: do we need to do anything with undefs here?
 								//  Note that the path(s) must be translated from project relative 
 								//  to top build directory relative
 								String[] paths = new String[allRes.size()];
@@ -3135,6 +3136,7 @@ public class GnuMakefileGenerator implements IManagedBuilderMakefileGenerator2 {
 								optType == IOption.LIBRARY_FILES ||
 								optType == IOption.MACRO_FILES) {
 							outputList = (List)option.getValue();
+							((Tool)tool).filterValues(optType, outputList);
 							// Add outputPrefix to each if necessary
 							if (outputPrefix.length() > 0) {
 								for (int j=0; j<outputList.size(); j++) {
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/ManagedBuildGnuToolInfo.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/ManagedBuildGnuToolInfo.java
index d2b58fd7c31..35808901420 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/ManagedBuildGnuToolInfo.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/makegen/gnu/ManagedBuildGnuToolInfo.java
@@ -201,6 +201,7 @@ public class ManagedBuildGnuToolInfo implements IManagedBuildGnuToolInfo {
 								optType == IOption.LIBRARY_FILES ||
 								optType == IOption.MACRO_FILES) {
 							inputs = (List)option.getValue();
+							tool.filterValues(optType, inputs);
 						}
 						for (int j=0; j<inputs.size(); j++) {
 							String inputName = (String)inputs.get(j);
@@ -385,6 +386,7 @@ public class ManagedBuildGnuToolInfo implements IManagedBuildGnuToolInfo {
 								optType == IOption.LIBRARY_PATHS ||
 								optType == IOption.LIBRARY_FILES ||
 								optType == IOption.MACRO_FILES) {
+							//TODO: do we need to do anything with undefs here?
 							//  Mote that when using the enumerated inputs, the path(s) must be translated from project relative 
 							//  to top build directory relative
 							String[] paths = new String[itEnumeratedInputs.size()];
@@ -539,6 +541,7 @@ public class ManagedBuildGnuToolInfo implements IManagedBuildGnuToolInfo {
 								optType == IOption.LIBRARY_FILES ||
 								optType == IOption.MACRO_FILES) {
 							outputs = (List)option.getValue();
+							tool.filterValues(optType, outputs);
 							// Add outputPrefix to each if necessary
 							if (outputPrefix.length() > 0) {
 								for (int j=0; j<outputs.size(); j++) {
diff --git a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildOptionSettingsUI.java b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildOptionSettingsUI.java
index b6311e8e9f3..5d8bdb67141 100644
--- a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildOptionSettingsUI.java
+++ b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildOptionSettingsUI.java
@@ -160,7 +160,12 @@ public class BuildOptionSettingsUI extends AbstractToolSettingUI {
 						case IOption.LIBRARY_PATHS:
 						case IOption.LIBRARY_FILES:
 						case IOption.MACRO_FILES:
-						{
+						case IOption.UNDEF_INCLUDE_PATH:
+						case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+						case IOption.UNDEF_INCLUDE_FILES:
+						case IOption.UNDEF_LIBRARY_PATHS:
+						case IOption.UNDEF_LIBRARY_FILES:
+						case IOption.UNDEF_MACRO_FILES:						{
 							fieldEditor = new FileListControlFieldEditor(optId, opt.getName(), opt.getToolTip(), fieldEditorParent, opt.getBrowseType());
 						} break;
 						
@@ -268,6 +273,12 @@ public class BuildOptionSettingsUI extends AbstractToolSettingUI {
 					case IOption.LIBRARY_PATHS:
 					case IOption.LIBRARY_FILES:
 					case IOption.MACRO_FILES:
+					case IOption.UNDEF_INCLUDE_PATH:
+					case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+					case IOption.UNDEF_INCLUDE_FILES:
+					case IOption.UNDEF_LIBRARY_PATHS:
+					case IOption.UNDEF_LIBRARY_FILES:
+					case IOption.UNDEF_MACRO_FILES:	
 						String[] listVal = (String[])((List)clonedOption.getValue()).toArray(new String[0]);
 						setOption = ManagedBuildManager.setOption(realCfg, realHolder, realOption, listVal);	
 						
@@ -412,6 +423,12 @@ public class BuildOptionSettingsUI extends AbstractToolSettingUI {
 					case IOption.LIBRARY_PATHS:
 					case IOption.LIBRARY_FILES:
 					case IOption.MACRO_FILES:
+					case IOption.UNDEF_INCLUDE_PATH:
+					case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+					case IOption.UNDEF_INCLUDE_FILES:
+					case IOption.UNDEF_LIBRARY_PATHS:
+					case IOption.UNDEF_LIBRARY_FILES:
+					case IOption.UNDEF_MACRO_FILES:
 						if(fe instanceof FileListControlFieldEditor){
 							String val[] =((FileListControlFieldEditor)fe).getStringListValue();
 							ManagedBuildManager.setOption(fInfo, changedHolder, changedOption, val);
diff --git a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildToolSettingUI.java b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildToolSettingUI.java
index 1deeb4aedc0..c15308b9bac 100644
--- a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildToolSettingUI.java
+++ b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/BuildToolSettingUI.java
@@ -330,6 +330,12 @@ public class BuildToolSettingUI extends AbstractToolSettingUI {
 							case IOption.LIBRARY_PATHS:
 							case IOption.LIBRARY_FILES:
 							case IOption.MACRO_FILES:
+							case IOption.UNDEF_INCLUDE_PATH:
+							case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+							case IOption.UNDEF_INCLUDE_FILES:
+							case IOption.UNDEF_LIBRARY_PATHS:
+							case IOption.UNDEF_LIBRARY_FILES:
+							case IOption.UNDEF_MACRO_FILES:
 								if (opt.getCommand() != null
 										&& optionValue.startsWith(opt
 												.getCommand())) {
diff --git a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsPrefStore.java b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsPrefStore.java
index 70017a47c0c..e7fc723597c 100644
--- a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsPrefStore.java
+++ b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsPrefStore.java
@@ -289,6 +289,12 @@ public class ToolSettingsPrefStore implements IPreferenceStore {
 					case IOption.LIBRARY_PATHS:
 					case IOption.LIBRARY_FILES:
 					case IOption.MACRO_FILES:
+					case IOption.UNDEF_INCLUDE_PATH:
+					case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+					case IOption.UNDEF_INCLUDE_FILES:
+					case IOption.UNDEF_LIBRARY_PATHS:
+					case IOption.UNDEF_LIBRARY_FILES:
+					case IOption.UNDEF_MACRO_FILES:
 						if(value instanceof String){
 							String val[] = parseString((String)value);
 							newOption = rcInfo.setOption(holder,option,val);
diff --git a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsTab.java b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsTab.java
index 7c46620dd88..975bb63ed3f 100644
--- a/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsTab.java
+++ b/build/org.eclipse.cdt.managedbuilder.ui/src/org/eclipse/cdt/managedbuilder/ui/properties/ToolSettingsTab.java
@@ -486,6 +486,12 @@ public class ToolSettingsTab extends AbstractCBuildPropertyTab implements IPrefe
 					case IOption.LIBRARY_PATHS:
 					case IOption.LIBRARY_FILES:
 					case IOption.MACRO_FILES:
+					case IOption.UNDEF_INCLUDE_PATH:
+					case IOption.UNDEF_PREPROCESSOR_SYMBOLS:
+					case IOption.UNDEF_INCLUDE_FILES:
+					case IOption.UNDEF_LIBRARY_PATHS:
+					case IOption.UNDEF_LIBRARY_FILES:
+					case IOption.UNDEF_MACRO_FILES:
 						String[] data = (String[])((List)option.getValue()).toArray(new String[0]);
 						setOption = ManagedBuildManager.setOption(fInfo, holder, option, data);
 						break;
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/settings/model/util/EntryStore.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/settings/model/util/EntryStore.java
index b2ff499358e..c9bd08c6329 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/settings/model/util/EntryStore.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/core/settings/model/util/EntryStore.java
@@ -62,6 +62,11 @@ public class EntryStore {
 		
 		return (ICLanguageSettingEntry[])result.toArray(new ICLanguageSettingEntry[result.size()]);
 	}
+	
+	public boolean containsEntries(int kind){
+		List list = getEntriesList(kind);
+		return list != null && list.size() != 0;
+	}
 
 	public ICLanguageSettingEntry[] getEntries(int kind){
 		List list = getEntriesList(kind);
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CLanguageSetting.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CLanguageSetting.java
index 0caaf7ef20e..d3edfdfce90 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CLanguageSetting.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CLanguageSetting.java
@@ -290,11 +290,13 @@ public class CLanguageSetting extends CDataProxy implements
 		EntryStore store = new EntryStore();
 //		KindBasedStore nameSetStore = new KindBasedStore();
 		int eKind;
-		for(Iterator iter = list.iterator(); iter.hasNext();){
-			ICLanguageSettingEntry entry = (ICLanguageSettingEntry)iter.next();
-			eKind = entry.getKind();
-			if((kind & eKind) != 0 && (data.getSupportedEntryKinds() & eKind) != 0){
-				store.addEntry(entry);
+		if(list != null){
+			for(Iterator iter = list.iterator(); iter.hasNext();){
+				ICLanguageSettingEntry entry = (ICLanguageSettingEntry)iter.next();
+				eKind = entry.getKind();
+				if((kind & eKind) != 0 && (data.getSupportedEntryKinds() & eKind) != 0){
+					store.addEntry(entry);
+				}
 			}
 		}
 		
@@ -307,7 +309,7 @@ public class CLanguageSetting extends CDataProxy implements
 
 //		int kinds[] = KindBasedStore.getSupportedKinds();
 		for(int i = 0; i < kinds.length; i++){
-			ICLanguageSettingEntry sortedEntries[] = store.getEntries(kinds[i]);
+			ICLanguageSettingEntry sortedEntries[] = store.containsEntries(kinds[i]) ? store.getEntries(kinds[i]) : null;
 			if((kind & kinds[i]) != 0)
 				data.setEntries(kinds[i], sortedEntries);
 		}
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/newui/AbstractLangsListTab.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/newui/AbstractLangsListTab.java
index 85423db8bf6..de2a1329e3f 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/newui/AbstractLangsListTab.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/newui/AbstractLangsListTab.java
@@ -171,8 +171,8 @@ public abstract class AbstractLangsListTab extends AbstractCPropertyTab {
 		boolean canDelete = canEdit;
 		if (canExport) {
 			ICLanguageSettingEntry ent = (ICLanguageSettingEntry)(table.getItem(index).getData());
-			if (ent.isReadOnly()) canEdit = false;
-			if (ent.isBuiltIn() || ent.isReadOnly()) canDelete = false;
+			if (ent.isBuiltIn() || ent.isReadOnly()) canEdit = false;
+			if (/*ent.isBuiltIn() || */ent.isReadOnly()) canDelete = false;
 		}
     	boolean canMoveUp = canDelete && index > 0;
     	boolean canMoveDown = canDelete && (index < table.getItemCount() - 1); 
@@ -346,7 +346,7 @@ public abstract class AbstractLangsListTab extends AbstractCPropertyTab {
 		case 2: // delete
 			if (n == -1) return;
 			old = (ICLanguageSettingEntry)(table.getItem(n).getData());
-			if (old.isReadOnly() || old.isBuiltIn()) return;
+			if (old.isReadOnly() /*|| old.isBuiltIn()*/) return;
 			incs.remove(old);
 			lang.setSettingEntries(getKind(), incs);
 			update();
@@ -409,7 +409,7 @@ public abstract class AbstractLangsListTab extends AbstractCPropertyTab {
 		}
 	}
 	protected void performDefaults() {
-		lang.setSettingEntries(getKind(), new ArrayList());
+		lang.setSettingEntries(getKind(), (List)null);
 		updateData(this.getResDesc());
 	}