On Thu, 30 May 2019 at 15:12, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Richard Copley <rcopley@gmail.com>
> > Date: Thu, 30 May 2019 14:04:26 +0100
> >
> > Emacs master fails to build in MinGW-W64 (MSYS2).
> >
> > The cause seems to be that since the configuration changes in commit
> "Update from Gnulib" of Wed May 29
> > 16:33:51 2019 -0700, we now include pthread_signal.h
> > (<
> https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-libraries/winpthreads/include/pthread_signal.h
> >)
> > which does this:
> >
> > #define pthread_sigmask(H, S1, S2) 0
> >
> > The result:
> >
> > gcc  -c -mtune=generic   -DUSE_CRT_DLL=1 -I /c/projects/emacs/nt/inc
> -mtune=generic  -MMD -MF
> > deps/pthread_sigmask.d -MP -fno-common -O2 -I. -I../src -I. -I./../src
> pthread_sigmask.c
> > In file included from
> C:/msys64/mingw64/x86_64-w64-mingw32/include/signal.h:10,
> >                  from pthread_sigmask.c:20:
> > pthread_sigmask.c:34:1: error: expected identifier or '(' before numeric
> constant
> >    34 | pthread_sigmask (int how, const sigset_t *new_mask, sigset_t
> *old_mask)
> >       | ^~~~~~~~~~~~~~~
>
> This doesn't happen to me, but I don't use MinGW64.
>
> Can you spot the part of the changes which caused us to include
> pthread_signal.h?  We shouldn't include any part of pthreads in the
> Windows build.
>

Not beyond the obvious (it's the pthread_sigmask.m4 changes), no. Sorry.
Prior to this change, lib\pthread_sigmask.c wasn't compiled at all AFAICS.