Re: autoconf enhancement for Interix

[Bruno Haible]

Eric Blake wrote:
> Here's the corresponding gnulib patch.  OK to apply?

I would feel a little safer if you would turn the AC_REQUIRE([AC_GNU_SOURCE])
into AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) rather than omitting them. If
some piece of autoconf macro needs to be used at "early" time, this
ordering constraint is relevant. You're betting on the fact that the macros
are not used "early". There's no big reason to bet on this: An AC_REQUIRE
does not cost any size in the configure file.

The patch to m4/lock.m4 has this problem, and also another one: lock.m4 is
used as part of the gettext infrastructure, which requires only autoconf
>= 2.54 and should not include extensions.m4. - Can you change m4/lock.m4
to use AC_USE_SYSTEM_EXTENSIONS only in autoconf version >= 2.62, and
AC_GNU_SOURCE otherwise? Something like

  m4_if(m4_version_compare(m4_defn([m4_PACKAGE_VERSION]),[2.62]),[-1],
    [AC_REQUIRE([AC_GNU_SOURCE])],
    [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])])

Bruno