Re: LT_AC_PROG_SED

[Ralf Wildenhues]

Hi Thomas,

Thanks, several bugs for the price of one bug report.

* Thomas Porschberg wrote on Tue, Jan 17, 2006 at 08:27:45AM CET:
> 
> I meet a problem with a configure.ac script which
> does call LT_AC_PROG_SED.
> However SED is not substituted with the sed command
> and the configure failed.
> I hardcoded SED=sed as a workaround and it worked.

1) Which package is this?  LT_AC_PROG_SED is going away,
   we had hoped nobody else would use it.  Does the package
   call it directly or does it AC_REQUIRE([LT_AC_PROG_SED])?
2) LT_AC_PROG_SED should AC_SUBST([SED]), as CVS Libtool does
   in its AC_PROG_SED copy.  Would that solve the issue you?
   Please post the failure and some context, then try with
   adding the AC_SUBST to your configure.ac and redo.

> Does the call of LT_AC_PROG_SED has any preconditions,
> what must I call before LT_AC_PROG_SED in configure.ac or
> do I need a very recent version of libtool ?

No, but it's not published interface.  The next Autoconf version
has AC_PROG_SED, which should be used instead, when that is released.

> I use libtoolize (GNU libtool) 1.5.18 which comes
> with my linux distribution.
> In which version was LT_AC_PROG_SED introduced ?

In 1.5.

Other quite serious bug:

3) In CVS HEAD Libtool, we use
   m4_ifndef([AC_PROG_SED],[
   AC_DEFUN([AC_PROG_SED], [...])
   ])

This will cause aclocal (at least up to 1.7, lower than 1.9) to
always pull in this libtool.m4.  Even if the user does not use
AC_PROG_LIBTOOL at all, as in:
  AC_INIT
  AC_PROG_SED
  AC_OUTPUT

Wouldn't it make sense to release Libtool 2.0 after Autoconf
2.60, AC_PREREQ(2.60) and drop our AC_PROG_SED?  What other options
do we have?  Wouldn't m4_define'ing AC_PROG_SED suffice for libtool.m4?

4) In CVS libtool, we don't provide backward compatibility for
   LT_AC_PROG_SED.  We probably should.

Cheers,
Ralf