* fix compilation errors in xorg, and with versions of allegro which don't
    define GFX_XWINDOWS_FULLSCREEN. Also this one works with gcc-4, no more
    errors about movl.
  * Apply patch from Antiriad which adds fix eight bootleg
  * Basic dependencies support in the makefile, so that at least the
    compilation doesn't stop with 2 pages of error messages just because
    we forgot to install a lib (liballeg, sdl and allegro tested).
  * use only -O1 for the optimizations in linux too :
    with -O4 it crashes dfeveron after the copyright screen (gcc4)
    and with gcc-3.4 you get a black screen when starting any game.
    All these are fixed by -O1, so I switch to -O1 for now (this is already
    the case for the windows version).
  * fix the stupid segfault in multchmp (it crashes only the windows and dos
    version apparently !)