Hide SDL_wcstoll and SDL_wcstoull for compilers not supporting long long (#15808)

Co-authored-by: Sam Lantinga <slouken@libsdl.org>

include/SDL3/SDL_stdinc.h

@@ -3081,6 +3081,7 @@ extern SDL_DECLSPEC long SDLCALL SDL_wcstol(const wchar_t *str, wchar_t **endp,
  */
 extern SDL_DECLSPEC unsigned long SDLCALL SDL_wcstoul(const wchar_t *str, wchar_t **endp, int base);
 
+#ifndef SDL_NOLONGLONG
 /**
  * Parse a `long long` from a wide string.
  *
@@ -3137,6 +3138,8 @@ extern SDL_DECLSPEC long long SDLCALL SDL_wcstoll(const wchar_t *str, wchar_t **
  */
 extern SDL_DECLSPEC unsigned long long SDLCALL SDL_wcstoull(const wchar_t *str, wchar_t **endp, int base);
 
+#endif /* !SDL_NOLONGLONG */
+
 /**
  * This works exactly like strlen() but doesn't require access to a C runtime.
  *