Hello,

i am using archlinux with GNU sed version 4.2.2 which generate with 'sed --version':

sed (GNU sed) 4.2.2
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Jay Fenlason, Tom Lord, Ken Pizzini,
and Paolo Bonzini.
GNU sed home page: <http://www.gnu.org/software/sed/>.
General help using GNU software: <http://www.gnu.org/gethelp/>.
E-mail bug reports to: <bug-sed@gnu.org>.
Be sure to include the word ``sed'' somewhere in the ``Subject:'' field.


This will fail on sed version check in configure.ac:
SED_VERSION=`$SED --version 2>/dev/null | $SED -ne "s/.*version \([[0-9\.]]*\)/\1/p"`


With command 'sed --version 2>/dev/null | sed -ne "s/.*version \([[0-9\.]]*\)/\1/p"' I got following output:
"3 or later <http://gnu.org/licenses/gpl.html>."

and configure failed with:
checking sed version... configure: error: we need at least GNU sed 4.x


GNU sed gets version string from gnulib see
http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/version-etc.c;hb=dbed1625626c6d6f271b715f87fd0930d8e68c2f
beginning at line 43.

I don't see a "version" substring there, maybe it isn't the best way to match the sed version.

Regards
Alexander Aring