Removed comma at end of enum in a public header, to make -Wpedantic happy.

include/SDL_syswm.h

@@ -111,7 +111,7 @@ typedef enum
     SDL_SYSWM_UIKIT,
     SDL_SYSWM_WAYLAND,
     SDL_SYSWM_MIR,
-    SDL_SYSWM_WINRT,
+    SDL_SYSWM_WINRT
 } SDL_SYSWM_TYPE;
 
 /**