Add some safeguards against wrong Qt bridge builds

Signed-off-by: falkTX <falktx@falktx.com>

Makefile

@@ -78,6 +78,9 @@ ALL_LIBS += $(3RD_LIBS)
 
 3rd: $(3RD_LIBS)
 	@$(MAKE) -C source/theme
+ifeq ($(HAVE_QT4),true)
+	@$(MAKE) -C source/bridges-ui ui_lv2-qt4
+endif
 
 libs: $(ALL_LIBS)
 

source/bridges-ui/CarlaBridgeToolkitQt.cpp

@@ -23,9 +23,15 @@
 #include <QtCore/QTimerEvent>
 
 #if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
+# ifdef BRIDGE_QT4
+#  error Wrong includes for this bridge!
+# endif
 # include <QtWidgets/QApplication>
 # include <QtWidgets/QMainWindow>
 #else
+# ifdef BRIDGE_QT5
+#  error Wrong includes for this bridge!
+# endif
 # include <QtGui/QApplication>
 # include <QtGui/QMainWindow>
 # ifdef HAVE_X11