[PATCH] Fix build issues with mingw toolchain

[Eli Zaretskii]

> Date: Tue, 14 May 2024 19:47:48 +0100
> Cc: tromey@adacore.com, ssbssa@yahoo.de, bernd.edlinger@hotmail.de,
>  gdb-patches@sourceware.org
> From: Pedro Alves <pedro@palves.net>
> 
> > I build GDB using mingw.org's MinGW, which does support XP (and older
> > versions as well), but its pthreads are a different matter -- I had
> > trouble with them and removed it from my system to avoid that.  Plus,
> > I'm not sure mingw.org's libstc++ supports <thread> if you build for
> > Posix threading (it definitely does NOT support <thread> for w32
> > threading).
> > 
> > So once again, we should actually try this before we conclude it's
> > possible.
> 
> OK.  I will have to leave that for someone who actually has such a system.
> I do not have one handy.
> 
> There is also this:
> 
>  https://github.com/meganz/mingw-std-threads
> 
> Described as:
> 
> "mingw-std-threads
>  Implementation of standard C++11 threading classes, which are currently still missing on MinGW GCC.
> 
>  Target Windows version
>  This implementation should work with Windows XP (regardless of service pack), or newer. The library automatically
>  detects the version of Windows that is being targeted (at compile time), and selects an implementation that
>  takes advantage of available Windows features. (...)."

I know.  But AFAIR integrating it with libstdc++ is not a simple job,
and no one has done that yet.

> >> Also, "--enable-threading=yes" silently ends up with threading disabled if std::thread
> >> doesn't work.  I think that's a bug.  If I explicitly request threading, and then
> >> configure detects std::thread doesn't work, it should error out.
> > 
> > Agreed.
> > 
> 
> I sent a patch for that, now:
> 
> https://inbox.sourceware.org/gdb-patches/20240514184341.1399428-1-pedro@palves.net/T/#u

Thanks.