[Xcb] pthread stubs in libX11 vs. libxcb

[Josh Triplett]

On Thu, Sep 29, 2022 at 05:45:28PM +0200, Uli Schlachter wrote:
> Hi,
> 
> Am 29.09.22 um 06:27 schrieb Keith Packard:
> > Alan Coopersmith <alan.coopersmith at oracle.com> writes:
> > 
> > > Does anyone disagree?
> > 
> > Yeah, synchronizing with xcb seems 'obviously right. The only question
> > I've got is that in 2022, should xcb ever use stubs for the thread functions?
> 
> No, it shouldn't. That's why since 2017, pthread-stub just links against
> pthread. It only does not do that if libc already includes the necessary
> stubs. See https://gitlab.freedesktop.org/xorg/lib/pthread-stubs/-/commit/8340ebd656c7e1a5b6d31170c1f3c87df043e793

At this point, I wonder if we should even have libpthread-stubs at all
(other than for backwards compatibility), versus just *unconditionally*
linking libxcb against whatever library is necessary to obtain pthreads
symbols.

In 2022, it *seems* like single-threaded applications are really
unlikely to be bottlenecked on X protocol (rather than numerous other
things through which more data will flow) to the degree that omitting
locking will make the difference between them being functional and not;
that's not worth the safety and correctness issues that attempting to do
so introduces.