diff --git a/build/org.eclipse.cdt.build.gcc.core/src/org/eclipse/cdt/build/gcc/core/GCCToolChain.java b/build/org.eclipse.cdt.build.gcc.core/src/org/eclipse/cdt/build/gcc/core/GCCToolChain.java
index 2c3f56b0e27..fb521623dae 100644
--- a/build/org.eclipse.cdt.build.gcc.core/src/org/eclipse/cdt/build/gcc/core/GCCToolChain.java
+++ b/build/org.eclipse.cdt.build.gcc.core/src/org/eclipse/cdt/build/gcc/core/GCCToolChain.java
@@ -471,6 +471,9 @@ public class GCCToolChain extends PlatformObject implements IToolChain {
 						} else {
 							try {
 								Path dirPath = Paths.get(dir);
+								if (!dirPath.isAbsolute()) {
+									dirPath = buildDirectory.resolve(dirPath);
+								}
 								if (Files.isDirectory(dirPath)) {
 									includePath.add(dirPath.toString());
 								}