remove SDLMain.m as an explicit libMac.a sourcee to prevent and support various broken versions of autoconf+automake.  instead add an explicit build rule and add to libMac.a via LIBADD.
remove SDLMain.m as an explicit libMac.a sourcee to prevent and support various broken versions of autoconf+automake.  instead add an explicit build rule and add to libMac.a via LIBADD.


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