Fixed updated return value for SDL_GL_SwapWindow()

Ozkan Sezer

http://hg.libsdl.org/SDL/rev/464a2676d8ab seems to have
forgotten removing the return from SDL_dynapi_procs.h, and this patch
does that. Without it, MSVC warns:
c:\sdl2\src\dynapi\SDL_dynapi_procs.h(598) : warning C4098:
'SDL_GL_SwapWindow_DEFAULT' : 'void' function returning a value
c:\sdl2\src\dynapi\SDL_dynapi_procs.h(598) : warning C4098:
'SDL_GL_SwapWindow' : 'void' function returning a value

src/dynapi/SDL_dynapi_procs.h

@@ -595,7 +595,7 @@ SDL_DYNAPI_PROC(SDL_GLContext,SDL_GL_GetCurrentContext,(void),(),return)
 SDL_DYNAPI_PROC(void,SDL_GL_GetDrawableSize,(SDL_Window *a, int *b, int *c),(a,b,c),)
 SDL_DYNAPI_PROC(int,SDL_GL_SetSwapInterval,(int a),(a),return)
 SDL_DYNAPI_PROC(int,SDL_GL_GetSwapInterval,(void),(),return)
-SDL_DYNAPI_PROC(void,SDL_GL_SwapWindow,(SDL_Window *a),(a),return)
+SDL_DYNAPI_PROC(void,SDL_GL_SwapWindow,(SDL_Window *a),(a),)
 SDL_DYNAPI_PROC(void,SDL_GL_DeleteContext,(SDL_GLContext a),(a),)
 SDL_DYNAPI_PROC(int,SDL_vsscanf,(const char *a, const char *b, va_list c),(a,b,c),return)
 SDL_DYNAPI_PROC(int,SDL_GameControllerAddMappingsFromRW,(SDL_RWops *a, int b),(a,b),return)