add HAVE_WGLGETCURRENTCONTEXT and the former HAVE_WAITFORSINGLEOBJECT and HAVE_SLEEP
add HAVE_WGLGETCURRENTCONTEXT and the former HAVE_WAITFORSINGLEOBJECT and HAVE_SLEEP


kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1