Comment # 2 on bug 1214460 from Richard Biener

The s390x crosses are old-style, just providing freestanding compilation.  I've
turned s390x, ppc64le and x86_64 targets to the full glibc variant in
devel:gcc, let's see if that works without further changes.

You can try installing from devel:gcc after the build finished.  Can you report
back whether the built packages work for you?