Don't automatically free temporary memory, let the application call SDL_FreeTemporaryMemory() when it's ready.

Also mark up all functions that return temporary memory with SDL_DECLSPEC_TEMP, to help people implementing language bindings.

Fixes https://github.com/libsdl-org/SDL/issues/10378

src/dynapi/gendynapi.py

@@ -197,6 +197,7 @@ def main():
             func_ret = func_ret.replace('extern', ' ')
             func_ret = func_ret.replace('SDLCALL', ' ')
             func_ret = func_ret.replace('SDL_DECLSPEC', ' ')
+            func_ret = func_ret.replace('SDL_DECLSPEC_TEMP', ' ')
             # Remove trailing spaces in front of '*'
             tmp = ""
             while func_ret != tmp: