Work in progress on multi-display support: * Added display parameter to many internal functions so video modes can be set on displays that aren't the public current one. * The fullscreen mode is associated with fullscreen windows - not displays, so different windows more naturally have a mode associated with them based on their width and height. It's no longer necessary to specify a fullscreen mode, a default one will be picked automatically for fullscreen windows.

define(AC_CHECK_DEFINE,[dnl
  AC_CACHE_CHECK(for $1 in $2, ac_cv_define_$1,
    AC_EGREP_CPP([YES_IS_DEFINED], [
#include <$2>
#ifdef $1
YES_IS_DEFINED
#endif
    ], ac_cv_define_$1=yes, ac_cv_define_$1=no)
  )
  if test "$ac_cv_define_$1" = "yes" ; then
    AC_DEFINE([HAVE_$1],[],[Added by AC_CHECK_DEFINE])
  fi
])dnl
AC_DEFINE([HAVE_$1],[],[Added by AC_CHECK_DEFINE])