[Bug driver/89587] New: gcc's rs6000 configuration unconditionally sets MULTIARCH_DIRNAME, even when multiarch is disabled

[awilfox at adelielinux dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89587

            Bug ID: 89587
           Summary: gcc's rs6000 configuration unconditionally sets
                    MULTIARCH_DIRNAME, even when multiarch is disabled
           Product: gcc
           Version: 8.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
          Assignee: unassigned at gcc dot gnu.org
          Reporter: awilfox at adelielinux dot org
  Target Milestone: ---
              Host: powerpc-linux-*
            Target: powerpc-linux-*

Simple reproduce is to build GCC to target powerpc-*-linux-*;
powerpc-unknown-linux-gnu and powerpc-foxkit-linux-musl both exhibit this
behaviour.

The config/rs6000/t-linux file unconditionally sets MULTIARCH_DIRNAME, even
when ./configure is passed --disable-multiarch.  This results in, for instance:

$ gcc -print-multiarch
powerpc-linux-musl

No other architecture's config file does this, other than powerpcspe, which is
already deprecated.