+AUTOCONF="autoconf"
+ACINCLUDE_FILES="lyxinclude.m4 libtool.m4 codeset.m4 gettext.m4 glibc21.m4 iconv.m4 isc-posix.m4 lcmessage.m4 progtest.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[234678])
+ EXTRA_ACINCLUDE_FILES="lyxinclude25x.m4"
+ ;;
+ *)
+ echo "This autoconf version is not supported by LyX."
+ echo "LyX only supports autoconf 2.5[234678]."
+ exit
+ ;;
+esac
+
+echo -n "Locating GNU m4... "
+GNUM4=
+for prog in $M4 gm4 gnum4 m4; do
+ # continue if $prog generates error (e.g. does not exist)
+ ( $prog --version ) < /dev/null > /dev/null 2>&1
+ if test $? -ne 0 ; then continue; fi
+
+ # /dev/null input prevents a hang of the script for some m4 compilers (e.g. on FreeBSD)
+ case `$prog --version < /dev/null 2>&1` in
+ *GNU*) GNUM4=$prog
+ break ;;
+ esac
+done
+if test x$GNUM4 = x ; then
+ echo "not found."
+ exit
+else
+ echo `which $GNUM4`
+fi
+
+# Generate acinclude.m4
+echo -n "Generate acinclude.m4... "
+rm -f acinclude.m4
+(cd config ; cat ${ACINCLUDE_FILES} ${EXTRA_ACINCLUDE_FILES} >../acinclude.m4)
+echo "done."