-ACINCLUDE_FILES="lyxinclude.m4 libtool.m4 codeset.m4 gettext.m4 glibc21.m4 iconv.m4 isc-posix.m4 lcmessage.m4 progtest.m4 xforms.m4 qt2.m4 gtk--.m4 gnome--.m4 gnome.m4 pspell.m4 pkg.m4"
-SIGCPP_ACINCLUDE_FILES="libtool.m4"
-
-echo -n "Locating GNU m4... "
-for prog in $M4 gm4 gnum4 m4 ; do
- case `$prog --version 2>&1` in
- *GNU*) ok=yes
- GNUM4=$prog
- echo "found: $GNUM4"
- break ;;
- *) ;;
- esac
+ # /dev/null input prevents a hang of the script for some m4 compilers (e.g. on FreeBSD)
+ case `$prog --version < /dev/null 2>&1` in
+ *GNU*) GNUM4=$prog
+ break ;;
+ esac