bug#64698: 29.0.92; on netbsd 9.3, gmake and "gmake bootstrap" fail to proceed

[Eli Zaretskii]

> Date: Thu, 20 Jul 2023 13:13:12 +0300
> From: Valtteri Vuorikoski <vuori@notcom.org>
> Cc: Paul Eggert <eggert@cs.ucla.edu>, van.ly@sdf.org, luangruo@yahoo.com, 
>       64698@debbugs.gnu.org
> 
> On Thu, Jul 20, 2023 at 07:47:40AM +0300, Eli Zaretskii wrote:
> > Valtteri, could you perhaps look into this?  Also, I'd be interested
> > to know why you didn't bump into this problem in your builds.
> 
> I've been building with --without-sound, and didn't have the ALSA
> library package installed either.
> 
> I don't have a machine where I could actually test whether sound comes
> out, but the alsa-lib package in NetBSD pkgsrc includes an internal
> type_compat.h header that does this:
> 
> #ifndef ESTRPIPE
> #define ESTRPIPE EPIPE
> #endif
> 
> Building emacs with sound enabled but alsa-lib _not_ installed seems
> to work (= compiles and starts) by using the system OSS library. Since
> Emacs's audio needs are modest, it may be better to use "bsd-ossaudio"
> on NetBSD if --with-sound=yes. AFAICT "ALSA" on NetBSD is just a proxy
> for the native audio system anyway.
> 
> The other option is to try and use ALSA if --with-sound=yes, but
> #ifdef out the ESTRPIPE branch if ESTRPIPE is not defined.
> 
> Personally I'd go with the default-to-ossaudio option, since pulling in
> alsa libraries introduces a pkgsrc dependency into the binary and doesn't
> seem like it provides a lot of benefit. I'm not quite sure what's the
> best way to convince configure.ac to act like this, but I can test
> patches at least on a compiles/doesn't-compile level.

Thanks.  I went with the #ifdef approach on the release branch, since
it's simpler and therefore safer.

Patches are welcome for preferring bsd-ossaudio on NetBSD.