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_gui/qt/project_wizard/content/path/QtProjectWizardContentPathCxxPch.cpp

@@ -0,0 +1,46 @@
+#include "QtProjectWizardContentPathCxxPch.h"
+
+#include "SourceGroupSettingsWithCxxPchOptions.h"
+#include "utility.h"
+#include "utilityFile.h"
+
+QtProjectWizardContentPathCxxPch::QtProjectWizardContentPathCxxPch(
+	std::shared_ptr<SourceGroupSettings> settings,
+	std::shared_ptr<SourceGroupSettingsWithCxxPchOptions> settingsCxxPch,
+	QtProjectWizardWindow* window
+)
+	: QtProjectWizardContentPath(window)
+	, m_settings(settings)
+	, m_settingsCxxPch(settingsCxxPch)
+{
+	setTitleString("Precompiled Header File");
+	setHelpString(
+		"Specify the path to the input header file that should be used to generate a precompiled header during indexing.<br />"
+		"If the indexed source code is usually built using precompiled headers, using this option will speed up your indexing performance.<br />"
+		"Leave blank to disable the use of precompiled headers. You can make use of environment variables with ${ENV_VAR}."
+	);
+	setAllowEmpty(true);
+	setPlaceholderString("Not Using Precompiled Headers");
+}
+
+void QtProjectWizardContentPathCxxPch::populate(QGridLayout* layout, int& row)
+{
+	QtProjectWizardContentPath::populate(layout, row);
+
+	m_picker->setPickDirectory(false);
+}
+
+void QtProjectWizardContentPathCxxPch::load()
+{
+	m_picker->setText(QString::fromStdWString(m_settingsCxxPch->getPchInputFilePath().wstr()));
+}
+
+void QtProjectWizardContentPathCxxPch::save()
+{
+	m_settingsCxxPch->setPchInputFilePathFilePath(FilePath(m_picker->getText().toStdWString()));
+}
+
+std::shared_ptr<SourceGroupSettings> QtProjectWizardContentPathCxxPch::getSourceGroupSettings()
+{
+	return m_settings;
+}