[Bug libstdc++/81797] gcc 7.1.0 fails to build on macOS 10.13 (High Sierra):

[chrisj at rtems dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797

--- Comment #19 from Chris Johns <chrisj at rtems dot org> ---
(In reply to Francois-Xavier Coudert from comment #18)
> Adding ".NOTPARALLEL: install-headers" to the libstdc++ Makefile fixes it
> perfectly, from what we can see on our apple-darwin test machines. We've now
> had dozens of compilations of GCC with no error, once that is applied.
> Without the patch, about ~70% of parallel compilations fail, on machines
> ranging from 2 to 8 cores.

Are you able to try an RTEMS tools build? It is a cross-compiler so I am
wondering if there is something still not right in this case.

I can push my changes to the RTEMS Source Builder tool we use to build tools
and post or send instructions.

> I'd like to suggest ".NOTPARALLEL: install-headers" to be considered as
> official patch.

The other solution is to unroll the shell loops and create the dependences. I
had to do this in RTEMS to get preinstalled headers to work.

Chris