libtool.m4 incompatibility with GNU textutils 2.0.21

[Paul Eggert]

libtool.m4 generates a shell script that uses the command `head -1',
but that isn't portable to textutils 2.0.21 when conforming to POSIX
1003.1-2001 (e.g. if the environment variable _POSIX2_VERSION set to
200112).  For example:

        $ head -1
        head: `-1' option is obsolete; use `-n 1'
        Try `head --help' for more information.
        $ head --version | sed 1q
        head (textutils) 2.0.21

Here is a patch.  This message is a followup to
<http://mail.gnu.org/pipermail/bug-libtool/2002-February/003050.html>
but I've simplified things by breaking out this one patch.

2002-05-04  Paul Eggert  <address@hidden>

        * libtool.m4 (AC_LIBTOOL_PROG_LD_SHLIBS): head -1 -> sed 1q
        to port to POSIX 1003.1-2001 hosts, like textutils 2.0.21
        with _POSIX2_VERSION=200112.

Index: libtool.m4
===================================================================
RCS file: /cvsroot/libtool/libtool/libtool.m4,v
retrieving revision 1.254
diff -p -u -r1.254 libtool.m4
--- libtool.m4  2 May 2002 14:22:51 -0000       1.254
+++ libtool.m4  4 May 2002 06:10:53 -0000
@@ -4539,7 +4539,7 @@ EOF
       # If the export-symbols file already is a .def file (1st line
       # is EXPORTS), use it as is.
       # If DATA tags from a recent dlltool are present, honour them!
-      _LT_AC_TAGVAR(archive_expsym_cmds, $1)='if test "x`head -1 
$export_symbols`" = xEXPORTS; then
+      _LT_AC_TAGVAR(archive_expsym_cmds, $1)='if test "x`sed 1q 
$export_symbols`" = xEXPORTS; then
          cp $export_symbols $output_objdir/$soname-def;
        else
          echo EXPORTS > $output_objdir/$soname-def;