Re: Failure building Emacs master on MSYS2 [MSYS2 PKG]

[Eli Zaretskii]

> From: Collin Funk <collin.funk1@gmail.com>
> Cc: angelo.g0@libero.it,  Eli Zaretskii <eliz@gnu.org>,  eggert@cs.ucla.edu,
>   emacs-devel@gnu.org
> Date: Wed, 07 May 2025 23:22:59 -0700
> 
> Hi Bruno,
> 
> Thanks for re-linking the reference to the "Moving MSYS(2) closer to
> Cygwin" document. I missed it while skimming through the thread...
> 
> > And in this case, Collin was kind enough to provide the analysis for the
> > MSYS people [1]. Namely, all the MSYS people need to do here is to upgrade
> > their GCC to version 13.4, 14.3, or 15.1. [2]
> 
> Yep, that should fix it.
> 
> Just to avoid any suprises, MSYS2 with a fixed GCC will fail until Emacs
> gets an update from Gnulib. Emacs m4/stddef_h.m4 has:
> 
>     AC_CACHE_CHECK([whether <stddef.h> is idempotent],
>       [gl_cv_stddef_idempotent],
>       [AC_COMPILE_IFELSE([AC_LANG_SOURCE(
>          [[
>          #if __GNUC__ == 13 || __GNUC__ == 14
>           #error "bug 114870 is present"
>          #endif
>          ]])],
>          [gl_cv_stddef_idempotent="guessing yes"],
>          [gl_cv_stddef_idempotent="guessing no"])
>       ])
> 
> This file was updated in Gnulib to account for the minor version fixes
> after it was last merged into Emacs:
> 
>     AC_CACHE_CHECK([whether <stddef.h> is idempotent],
>       [gl_cv_stddef_idempotent],
>       [AC_COMPILE_IFELSE([AC_LANG_SOURCE(
>          [[
>          #if \
>              ((__GNUC__ == 13 && __GNUC_MINOR__ <= 3) \
>               || (__GNUC__ == 14 && __GNUC_MINOR__ <= 2))
>           #error "bug 114870 is present"
>          #endif
>          ]])],
>          [gl_cv_stddef_idempotent="guessing yes"],
>          [gl_cv_stddef_idempotent="guessing no"])
> 
> I will let Eli and Paul decide if ./admin/merge-gnulib can be done.
> Since I know Emacs tries to avoid it near releases and I am not familiar
> with the release schedule (Emacs 30 feels recent though).

There should be no problem to merge from Gnulib on the master branch,
but that will only affect Emacs 31 and later.