build: allow to disable language support in cmake

* in addition: add unloadable sourcegroup to visualize, load and save information when loading a project that contains source groups that are not supported by the build

src/lib_gui/qt/project_wizard/content/paths/QtProjectWizardContentPathsHeaderSearchGlobal.cpp

@@ -1,5 +1,7 @@
 #include "QtProjectWizardContentPathsHeaderSearchGlobal.h"
 
+#if BUILD_CXX_LANGUAGE_PACKAGE
+
 #include <QMessageBox>
 
 #include "ApplicationSettings.h"
@@ -110,3 +112,5 @@ void QtProjectWizardContentPathsHeaderSearchGlobal::setPaths(const std::vector<F
 	m_list->addPaths({ ResourcePaths::getCxxCompilerHeaderPath() }, true);
 	m_list->addPaths(paths);
 }
+
+#endif // BUILD_CXX_LANGUAGE_PACKAGE