Re: Emacs pretest 28.0.90 is out

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Tue, 07 Dec 2021 10:16:06 +0800
> 
> It turns out that that's not the entirety of the problem: gnulib seems
> to define a lot of GL_GNULIB_FOO variables, which the sed scripts don't
> handle, but are used in each generated header.
> 
> What is the purpose of those variables, and what would be a suitable
> value to define them to?

They are used to produce #ifdef's and other preprocessor directives as
appropriate for the target platform, see how these are used in Sed
commands in gnulib.mk.in.

Gnulib changed their style some since the last time those Sed scripts
where tested.  Where previously they had something like

                -e 's/@''GNULIB_FCNTL''@/$(GNULIB_FCNTL)/g' \

they now use

                -e 's/@''GNULIB_FCNTL''@/$(GL_GNULIB_FCNTL)/g' \

So it means that sedlibmk.inp should be amended to use GL_GNULIB_foo
where previously it used GNULIB_foo.