pipewire: disable -Wdeclaration-after-statement for pipewire headers

Fixes: https://github.com/libsdl-org/SDL/issues/14343

src/audio/pipewire/SDL_pipewire.c

@@ -28,10 +28,19 @@
 #include "SDL_loadso.h"
 #include "SDL_pipewire.h"
 
+#if (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6))) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeclaration-after-statement"
+#endif
+
 #include <pipewire/extensions/metadata.h>
 #include <spa/param/audio/format-utils.h>
 #include <spa/utils/json.h>
 
+#if (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6))) || defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
 /*
  * The following keys are defined for compatability when building against older versions of Pipewire
  * prior to their introduction and can be removed if the minimum required Pipewire build version is