Fixed bug 4987 - Can't build on MinGW a recent state: conflicting types
Vitaly Novichkov
Recent attempt to build a recent HG state of SDL2 via AppVeyor gives the failure:
https://ci.appveyor.com/project/Wohlstand/sdl-mixer-x/builds/30821858/job/359gqvypi2f18nok
```
C:\projects\sdl-mixer-x\build-MinGW-w32-MinSizeRel-Win32-VB6-Binding\external\AudioCodecs\src\AudioCodecs-build\external\SDL2\src\SDL2HG\src\dynapi\SDL_dynapi_procs.h:56:29: error: conflicting types for 'SDL_CreateThread'
SDL_DYNAPI_PROC(SDL_Thread*,SDL_CreateThread,(SDL_ThreadFunction a, const char *b, void *c),(a,b,c),return)
1 file changed
