[Bug libstdc++/106162] libstdc++v3: bits/largefile-config.h.tmp: No such file or directory race condition

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106162

--- Comment #6 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #2)
> (In reply to Sergei Trofimovich from comment #0)
> > There is a race condition when (I speculate) libstdcv++v3 is built in
> > parallel from different 'make' processes. Perhaps for c++98 | c++11 | x++17
> > instances?
> 
> There are no such instances. It is built separately for each multilib, but
> each of those has its own $host_builddir

Aha, TIL!

> Are you 100% sure you didn't actually run multiple make processes yourself,
> e.g by using & instead of && in a shell command?

I was running it from a standard build script. Should be just 'make -j16 -l16'
(with a small caveat: make is built with --shuffle support to reorder what what
is allowed to expose missing depends:
https://savannah.gnu.org/bugs/index.php?62100).

(In reply to Jonathan Wakely from comment #5)
> Created attachment 53236 [details]
> Add missing prerequisite to generated header
> 
> I'm testing this.

Thank you! I'll also give it a go locally and will complain if it fails in a
similar way.