[#407] fix CompilerBuiltinsDetector for msys2 on Windows (#648)

[#407] fix CompilerBuiltinsDetector for msys2 on Windows

The cc.exe from mingw64 (part of Msys2) on Windows needs the bin folder
to be on the PATH to be executed. e.g. 'C:\msys64\mingw64\bin' must be
part of the PATH environment variable

fixes #407

jsoncdb/org.eclipse.cdt.jsoncdb.core/META-INF/MANIFEST.MF

@@ -4,7 +4,7 @@ Bundle-Name: %bundleName
 Bundle-Description: %bundleDescription
 Bundle-Copyright: %Bundle-Copyright
 Bundle-SymbolicName: org.eclipse.cdt.jsoncdb.core;singleton:=true
-Bundle-Version: 1.4.200.qualifier
+Bundle-Version: 1.4.300.qualifier
 Bundle-Vendor: %Bundle-Vendor
 Bundle-Localization: plugin
 Bundle-RequiredExecutionEnvironment: JavaSE-17

jsoncdb/org.eclipse.cdt.jsoncdb.core/src/org/eclipse/cdt/jsoncdb/core/internal/builtins/CompilerBuiltinsDetector.java

@@ -14,9 +14,11 @@ import java.nio.file.Files;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Objects;
 
+import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.ConsoleOutputStream;
 import org.eclipse.cdt.core.ICommandLauncher;
 import org.eclipse.cdt.core.resources.IConsole;
@@ -104,8 +106,8 @@ public class CompilerBuiltinsDetector {
 
 		launcher.setProject(project);
 		launcher.showCommand(console != null);
-		final Process proc = launcher.execute(new Path(command), argList.toArray(new String[argList.size()]), getEnvp(),
+		final Process proc = launcher.execute(new Path(command), argList.toArray(new String[argList.size()]),
-				new Path(this.buildDirectory.toString()), monitor);
+				getEnvp(project), new Path(this.buildDirectory.toString()), monitor);
 		if (proc != null) {
 			try {
 				// Close the input of the process since we will never write to it
@@ -182,20 +184,47 @@ public class CompilerBuiltinsDetector {
 	 * @return String array of environment variables in format "var=value". Does not
 	 *         return {@code null}.
 	 */
-	private String[] getEnvp() {
+	private String[] getEnvp(IProject project) {
+		var map = new HashMap<String, String>();
+		// The cc.exe from mingw64 (part of Msys2) on Windows needs the bin folder to be on the PATH to be executed.
+		// e.g. 'C:\msys64\mingw64\bin' must be part of the PATH environment variable. That's why we need PATH here:
+		// Fixes CDT #407
+		try {
+			final String path = "PATH"; //$NON-NLS-1$
+			var variables = CCorePlugin.getDefault().getBuildEnvironmentManager()
+					.getVariables(project.getActiveBuildConfig(), true);
+			for (var variable : variables) {
+				if (path.equalsIgnoreCase(variable.getName())) {
+					map.put(path, variable.getValue());
+					break;
+				}
+			}
+		} catch (CoreException e) {
+			Plugin.getDefault().getLog().error(
+					String.format(Messages.CompilerBuiltinsDetector_errmsg_determine_PATH_failed, project.getName()),
+					e);
+		}
 		// On POSIX (Linux, UNIX) systems reset language variables to default (English)
 		// with UTF-8 encoding since GNU compilers can handle only UTF-8 characters.
 		// Include paths with locale characters will be handled properly regardless
 		// of the language as long as the encoding is set to UTF-8.
 		// English language is set for parser because it relies on English messages
 		// in the output of the 'gcc -v'.
-		String[] strings = {
-				// override for GNU gettext
-				"LANGUAGE" + "=en", //$NON-NLS-1$//$NON-NLS-2$
-				// for other parts of the system libraries
-				"LC_ALL" + "=C.UTF-8" }; //$NON-NLS-1$ //$NON-NLS-2$
 
-		return strings;
+		// override for GNU gettext
+		map.put("LANGUAGE", "en"); //$NON-NLS-1$ //$NON-NLS-2$
+		// for other parts of the system libraries
+		map.put("LC_ALL", "C.UTF-8"); //$NON-NLS-1$ //$NON-NLS-2$
+
+		var envArray = map.entrySet().stream().map(entry -> {
+			var result = entry.getKey() + '=';
+			if (entry.getValue() != null) {
+				result = result + entry.getValue();
+			}
+			return result;
+		}).toArray(String[]::new);
+
+		return envArray;
 	}
 
 	/**

jsoncdb/org.eclipse.cdt.jsoncdb.core/src/org/eclipse/cdt/jsoncdb/core/internal/builtins/Messages.java

@@ -23,6 +23,7 @@ class Messages extends NLS {
 	public static String CompilerBuiltinsDetector_msg_detection_finished;
 	public static String CompilerBuiltinsDetector_msg_detection_start;
 	public static String CompilerBuiltinsDetector_msg_unexpectedly_still_running;
+	public static String CompilerBuiltinsDetector_errmsg_determine_PATH_failed;
 	public static String DetectorConsole_title;
 	static {
 		// initialize resource bundle

jsoncdb/org.eclipse.cdt.jsoncdb.core/src/org/eclipse/cdt/jsoncdb/core/internal/builtins/messages.properties

@@ -15,4 +15,5 @@ CompilerBuiltinsDetector_errmsg_command_failed=%1$s exited with status %2$d.
 CompilerBuiltinsDetector_msg_detection_finished=Detecting compiler built-ins took %d ms.
 CompilerBuiltinsDetector_msg_detection_start=%1$s Detecting compiler built-ins for project '%2$s'
 CompilerBuiltinsDetector_msg_unexpectedly_still_running=%1$s is unexpectedly still running. Some built-ins might not have been captured by the compiler built-ins detector.
+CompilerBuiltinsDetector_errmsg_determine_PATH_failed=Cannot determine PATH variable for project '%1$s'
 DetectorConsole_title=Compiler Built-ins Detection Console