[Bug bootstrap/91034] In tree build of gmp fails on Raspberry Pi4 (ARM Cortex A72) with `mls r1,r4,r8,r11' not supported in ARM mode

[andrewm.roberts at sky dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91034

--- Comment #6 from Andrew Roberts <andrewm.roberts at sky dot com> ---
I'm now building gcc 9.1.0 with the system gmp (using --with-gmp-lib and
--with-gmp-include). If this is successful I'll use this compiler to rebuild
itself with an in tree gmp and see where that gets me. Hopefully will allow the
elimination of the host gcc as a culprit.