On 2024-09-04 22:43, Eli Zaretskii wrote:

> Gnulib moved the prototypes of sig2str and str2sig from sig2str.h to
> Gnulib's signal.h, evidently assuming that a build which uses the
> Gnulib sig2str will also use the Gnulib signal.h header, but that
> assumption is false for the MinGW build of Emacs, which omits
> lib/signal.h (because it clashes with some w32 code in Emacs).
> 
> I fixed that temporarily by modifying lib/sig2str.h to include the
> missing stuff for MinGW, but this is really a Gnulib issue, and should
> be fixed in Gnulib, IMO.

The change to Gnulib was to align with POSIX.1-2024, which declares 
sig2str and str2sig in <signal.h>; see:

https://pubs.opengroup.org/onlinepubs/9799919799/functions/sig2str.html

We don't want sig2str callers to depart from the POSIX API, any more 
than we'd want to require (say) fdopen callers to include a 
Gnulib-specific fdopen.h rather than including <stdio.h>.

Instead, how about adjusting Emacs's MinGW shims to supply the missing 
declarations? Something like the attached patch, say. (I don't use MinGW 
so can't easily test this.)