build: ship clang compiler header within Sourcetrail package on macOS and Linux

* replace path to local compiler headers with packaged ones in include path detection
* added app settings migration to replace local compiler header path with path to packaged headers

src/lib/utility/utilityCxx.cpp

@@ -0,0 +1,28 @@
+#include "utility/utilityCxx.h"
+
+#include "utility/ResourcePaths.h"
+#include "utility/utilityApp.h"
+
+namespace utility
+{
+	std::vector<FilePath> replaceOrAddCxxCompilerHeaderPath(const std::vector<FilePath>& headerSearchPaths)
+	{
+		if (utility::getOsType() == OS_WINDOWS)
+		{
+			return headerSearchPaths;
+		}
+
+		std::vector<FilePath> newHeaderSearchPaths;
+
+		for (const FilePath& path : headerSearchPaths)
+		{
+			if (!path.getConcatenated(L"/stdarg.h").exists())
+			{
+				newHeaderSearchPaths.push_back(path);
+			}
+		}
+
+		newHeaderSearchPaths.push_back(ResourcePaths::getCxxCompilerHeaderPath().getCanonical());
+		return newHeaderSearchPaths;
+	}
+}