Remove redundant 'SDL_GetErrBuf' declaration

src/SDL_error.c

@@ -26,16 +26,6 @@
 #include "SDL_error.h"
 #include "SDL_error_c.h"
 
-
-/* Routine to get the thread-specific error variable */
-#if SDL_THREADS_DISABLED
-/* The default (non-thread-safe) global error variable */
-static SDL_error SDL_global_error;
-#define SDL_GetErrBuf() (&SDL_global_error)
-#else
-extern SDL_error *SDL_GetErrBuf(void);
-#endif /* SDL_THREADS_DISABLED */
-
 #define SDL_ERRBUFIZE   1024
 
 /* Private functions */

src/thread/SDL_thread.c

@@ -205,6 +205,11 @@ SDL_Generic_SetTLSData(SDL_TLSData *storage)
 SDL_error *
 SDL_GetErrBuf(void)
 {
+#if SDL_THREADS_DISABLED
+    /* Non-thread-safe global error variable */
+    static SDL_error SDL_global_error;
+    return &SDL_global_error;
+#else
     static SDL_SpinLock tls_lock;
     static SDL_bool tls_being_created;
     static SDL_TLSID tls_errbuf;
@@ -249,6 +254,7 @@ SDL_GetErrBuf(void)
         SDL_TLSSet(tls_errbuf, errbuf, SDL_free);
     }
     return errbuf;
+#endif /* SDL_THREADS_DISABLED */
 }