powerpc64 graphics/mesa-dri build failure in poudriere, system clang's /usr/bin/cc got assert failure: "Target supports vector op, but scalar requires expansion?"

[Jan Beich]

Mark Millard <marklmi at yahoo.com> writes:

> Unfortunately poudiere bulk tar archives of failures do not
> catch the /tmp/* material from:
>
> cc: error: unable to execute command: Abort trap (core dumped)
> cc: error: clang frontend command failed due to signal (use -v to see invocation)
> FreeBSD clang version 8.0.0 (tags/RELEASE_800/final 356365) (based on LLVM 8.0.0)
> Target: powerpc64-unknown-freebsd13.0
> Thread model: posix
> InstalledDir: /usr/bin

Do you have the build log? Maybe it's possible to reproduce simply by adding
-target powerpc64-unknown-freebsd13.0 while cross-building that particular file
using otherwise the same command line options as native build.