+AUTOCONF="autoconf"
+ACINCLUDE_FILES="lyxinclude.m4 libtool.m4 xforms.m4 qt.m4 gtk--.m4 gnome--.m4 gnome.m4 aspell.m4 pspell.m4 cygwin.m4 pkg.m4"
+
+# Discover what version of autoconf we are using.
+autoversion=`$AUTOCONF --version | head -n 1`
+
+echo "Using $autoversion"
+case $autoversion in
+ *2.5[2-9])
+ EXTRA_ACINCLUDE_FILES="lyxinclude25x.m4"
+ ;;
+ *)
+ echo "This autoconf version is not supported by LyX."
+ echo "LyX only supports autoconf 2.5[2-9]."
+ exit
+ ;;
+esac