QmlDesigner: Improve warning suppression

Can be removed with never compiler.

Change-Id: I3196acfc82e3ab53f0f72dec3b543f27b9bbe2e1
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/sqliteids.h

@@ -51,17 +51,10 @@ public:
         return first.id >= second.id;
     }
 
-#if defined(__GNUC__) && !defined(__clang__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
-#endif
     constexpr friend InternalIntegerType operator-(BasicId first, BasicId second)
     {
         return first.id - second.id;
     }
-#if defined(__GNUC__) && !defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
 
     constexpr bool isValid() const { return id > 0; }
 

src/plugins/qmldesigner/CMakeLists.txt

@@ -8,7 +8,8 @@ if (APPLE)
   set(QmlDesignerPluginInstallPrefix "${IDE_PLUGIN_PATH}/QmlDesigner")
 endif()
 
-
+add_compile_options("$<$<COMPILE_LANG_AND_ID:CXX,Clang>:-Wno-error=maybe-uninitialized>")
+add_compile_options("$<$<COMPILE_LANG_AND_ID:CXX,GNU>:-Wno-error=maybe-uninitialized>")
 
 add_qtc_library(QmlDesignerUtils STATIC
   DEPENDS