Only ignore -Wmaybe-uninitialized on GCC

An ifdef sounds like a better approach than ignoring two additional
warnings.

src/common/serialization/vst3/param-value-queue.h

@@ -27,9 +27,9 @@
 // FIXME: When used in a Boost.Containers small vector, GCC somehow complains
 //        that the fields in this class may be uninitialized (during the
 //        deserialization). This warning only shows up during a unity build.
-#pragma GCC diagnostic ignored "-Wpragmas"
-#pragma clang diagnostic ignored "-Wunknown-warning-option"
+#if defined(__GNUC__) && !defined(__llvm__)
 #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 
 /**
  * Wraps around `IParamValueQueue` for serializing a queue containing changes to

src/wine-host/xdnd-proxy.cpp

@@ -278,9 +278,9 @@ void WineXdndProxy::end_xdnd() {
 //        Oh and Clang doesn't know about -Wmaybe-uninitialized, so we need to
 //        ignore some more warnings here to get clangd to not complain
 #pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpragmas"
-#pragma clang diagnostic ignored "-Wunknown-warning-option"
+#if defined(__GNUC__) && !defined(__llvm__)
 #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 
 void WineXdndProxy::run_xdnd_loop() {
     const HWND windows_desktop_window = GetDesktopWindow();
@@ -656,9 +656,9 @@ std::optional<xcb_window_t> WineXdndProxy::get_xdnd_proxy(
 // FIXME: See above for more context, spurious warning is generated by passing
 //        `*last_xdnd_window` to this function
 #pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpragmas"
-#pragma clang diagnostic ignored "-Wunknown-warning-option"
+#if defined(__GNUC__) && !defined(__llvm__)
 #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 
 // NOLINTNEXTLINE(bugprone-easily-swappable-parameters)
 void WineXdndProxy::send_xdnd_message(xcb_window_t window,