logic: Implemented usage of PCH for indexing EmptyCxx Source Groups

* further change: initialize all llvm targets before indexing
* further change: remove configurable dependencies directory from gradle and maven sourcegroups

src/lib/project/SourceGroup.cpp

@@ -1,15 +1,22 @@
 #include "SourceGroup.h"
 
-#include "MemoryIndexerCommandProvider.h"
-#include "SourceGroupSettings.h"
 #include "FilePath.h"
 #include "FilePathFilter.h"
+#include "MemoryIndexerCommandProvider.h"
+#include "ProjectSettings.h"
+#include "SourceGroupSettings.h"
+#include "TaskLambda.h"
 
 std::shared_ptr<IndexerCommandProvider> SourceGroup::getIndexerCommandProvider(const std::set<FilePath>& filesToIndex) const
 {
 	return std::make_shared<MemoryIndexerCommandProvider>(getIndexerCommands(filesToIndex));
 }
 
+std::shared_ptr<Task> SourceGroup::getPreIndexTask(std::shared_ptr<DialogView> dialogView) const
+{
+	return std::make_shared<TaskLambda>([]() {});
+}
+
 SourceGroupType SourceGroup::getType() const
 {
 	return getSourceGroupSettings()->getType();