controllermap: use enum to avoid '-Wmaybe-uninitialized' Emitted by MinGW: In function 'WatchJoystick', inlined from 'SDL_main' at D:/a/SDL/SDL/test/controllermap.c:802:9: D:/a/SDL/SDL/test/controllermap.c:437:9: warning: 'marker' may be used uninitialized [-Wmaybe-uninitialized] 437 | SDL_SetTextureAlphaMod(marker, alpha); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ D:/a/SDL/SDL/test/controllermap.c: In function 'SDL_main': D:/a/SDL/SDL/test/controllermap.c:355:71: note: 'marker' was declared here 355 | SDL_Texture *background_front, *background_back, *button, *axis, *marker;