Only use GCC pragmas when we're building with GCC

src/SDL_error.c

@@ -116,8 +116,10 @@ SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
     return -1;
 }
 
+#ifdef __GNUC__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
+#endif
 /* This function has a bit more overhead than most error functions
    so that it supports internationalization and thread-safe errors.
 */
@@ -218,7 +220,9 @@ SDL_GetErrorMsg(char *errstr, int maxlen)
     }
     return (errstr);
 }
+#ifdef __GNUC__
 #pragma GCC diagnostic pop
+#endif
 
 /* Available for backwards compatibility */
 const char *