SDL_loadso.h: add missing SDLCALL to SDL_LoadFunction()

include/SDL3/SDL_loadso.h

@@ -89,8 +89,7 @@ extern DECLSPEC void *SDLCALL SDL_LoadObject(const char *sofile);
  * \sa SDL_LoadObject
  * \sa SDL_UnloadObject
  */
-extern DECLSPEC SDL_FunctionPointer SDL_LoadFunction(void *handle,
-                                                     const char *name);
+extern DECLSPEC SDL_FunctionPointer SDLCALL SDL_LoadFunction(void *handle, const char *name);
 
 /**
  * Unload a shared object from memory.