+# Test for windowing system
+case "${host}" in
+ *mingw32*) SYS="WIN" ;;
+ *cygwin*) SYS="WIN" ;;
+ *apple*) SYS="MAC" ;;
+ *) SYS="X11" ;;
+esac
+AC_SUBST([SYS])
+if test "$SYS" = "WIN"; then
+ ac_default_prefix="/"
+fi
+AM_CONDITIONAL([SYS_WIN], test "$SYS" = "WIN")
+AM_CONDITIONAL([SYS_MAC], test "$SYS" = "MAC")
+AM_CONDITIONAL([SYS_X11], test "$SYS" = "X11")
+