Re: expand-before-require bug

[Ralf Wildenhues]

* Eric Blake wrote on Mon, Jan 26, 2009 at 12:36:25AM CET:
> 
> Backporting within gnulib-common.m4 itself won't work - we have to
> redefine AC_DEFUN_ONCE before any other gnulib .m4 file that uses it to
> define another macro.  Fortunately, Automake collects all m4/*.m4 files in
> alphabetical order, so it should be as simple as making a file named
> 000-gnulib.m4 (or some-such) which is then guaranteed to be included
> before any other gnulib m4 file.  Any thoughts on how best to name/include
> such a file reliably?

I'd name it 000-gnulib-override.m4.  GCC's config/override.m4 uses this
to ensure aclocal includes it (the m4_PACKAGE_VERSION is only to avoid
errors with older Autoconf):

ifdef([m4_PACKAGE_VERSION],
[dnl AC_DEFUN a commonly used macro so this file is picked up.
m4_copy([AC_PREREQ], [_AC_PREREQ])
AC_DEFUN([AC_PREREQ], [frob])
m4_copy([_AC_PREREQ], [AC_PREREQ])
...])

Cheers,
Ralf