logic: Fixes and improvements for C/C++ compiler header path handling

* Always add compiler header path when prefilling on first start, regardless of successful detection
* Show compiler header path in path list box on top and readonly
* Prepend compiler header path on Windows in system header path compiler flags, append otherwise
* Show warning when saving ApplicationSettings if compiler header path is not in global include paths
* Show warning when saving ApplicationSettings if there is another path containing compiler headers

src/lib/settings/ApplicationSettings.cpp

@@ -13,7 +13,7 @@
 #include "UserPaths.h"
 #include "Version.h"
 
-const size_t ApplicationSettings::VERSION = 5;
+const size_t ApplicationSettings::VERSION = 6;
 
 std::shared_ptr<ApplicationSettings> ApplicationSettings::s_instance;
 
@@ -78,11 +78,11 @@ bool ApplicationSettings::load(const FilePath& filePath, bool readOnly)
 			}
 		}
 	));
-	migrator.addMigration(5, std::make_shared<SettingsMigrationLambda>(
+	migrator.addMigration(6, std::make_shared<SettingsMigrationLambda>(
 		[](const SettingsMigration* migration, Settings* settings)
 		{
 			std::vector<FilePath> cxxHeaderSearchPaths = migration->getValuesFromSettings(
-				settings, "indexing/cxx/header_search_paths/header_search_path", std::vector<FilePath>()); 
+				settings, "indexing/cxx/header_search_paths/header_search_path", std::vector<FilePath>());
 
 			cxxHeaderSearchPaths = utility::replaceOrAddCxxCompilerHeaderPath(cxxHeaderSearchPaths);
 

src/lib/utility/ResourcePaths.cpp

@@ -34,5 +34,5 @@ FilePath ResourcePaths::getJavaPath()
 
 FilePath ResourcePaths::getCxxCompilerHeaderPath()
 {
-	return AppPath::getAppPath().concatenate(L"data/cxx/include/");
+	return AppPath::getAppPath().concatenate(L"data/cxx/include/").getCanonical();
 }

src/lib/utility/utilityCxx.cpp

@@ -1,30 +1,23 @@
 #include "utilityCxx.h"
 
 #include "ResourcePaths.h"
-#include "utilityApp.h"
 
 namespace utility
 {
 	std::vector<FilePath> replaceOrAddCxxCompilerHeaderPath(const std::vector<FilePath>& headerSearchPaths)
 	{
 		std::vector<FilePath> newHeaderSearchPaths;
+		const FilePath cxxCompilerHeaderPath = ResourcePaths::getCxxCompilerHeaderPath();
 
-		if (utility::getOsType() == OS_WINDOWS)
+		for (const FilePath& path : headerSearchPaths)
 		{
-			newHeaderSearchPaths = headerSearchPaths;
-		}
-		else
-		{
-			for (const FilePath& path : headerSearchPaths)
+			if (path != cxxCompilerHeaderPath)
 			{
-				if (!path.getConcatenated(L"/stdarg.h").exists())
-				{
-					newHeaderSearchPaths.push_back(path);
-				}
+				newHeaderSearchPaths.push_back(path);
 			}
 		}
 
-		newHeaderSearchPaths.push_back(ResourcePaths::getCxxCompilerHeaderPath().getCanonical());
+		newHeaderSearchPaths.push_back(cxxCompilerHeaderPath);
 		return newHeaderSearchPaths;
 	}
 }