Remove macro definition for SDL_ERRBUFIZE

I was looking at how errors are handled by SDL and came across this #define SDL_ERRBUFIZE which looks like a typo for SDL_ERRBUFSIZE, but either way, it looks like this isn't being used anywhere anymore because it was getting reported whenever I compile SDL with -Wunused-macros, and the last time it was mentioned in the code was from commit 09ca66b.

src/SDL_error.c

@@ -25,8 +25,6 @@
 #include "SDL_error.h"
 #include "SDL_error_c.h"
 
-#define SDL_ERRBUFIZE   1024
-
 int
 SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...)
 {