Comment # 41 on bug 1185952 from Michael Matz

(In reply to Aaron Puchert from comment #40)
> (In reply to Reinhard Max from comment #39)
> > I've seen this happen on all three versions of PostgreSQL that support LLVM
> > (11, 12 and 13), but only on s390x and only in about 4 out of 5 build runs
> > (within the short period over which I monitored it).
> 
> Since it comes from ld (or collect2?) and that's an LTO link, I suppose it
> might be a race condition. I agree, it should be a separate bug. Maybe add
> Michael Matz for binutils and Martin Liska for GCC LTO. IBM tends to have
> weaker memory models, and that race might just not materialize with the
> stronger model of x86.

I was involved for that already.  I never was able to reproduce it with a local
build (on s390x of course), with none of the postgres packages.  And triggering
a rebuild of an affected package, even if it got to the same build machine,
sometime
also makes it build through (just to fail on the next rebuilds again).  So,
it's most definitely a race somewhere, but without being at least somewhat
locally reproducable it's hopeless.