[Bug target/98139] varasm.c fails to compile on AIX 7.2: -Werror=unused-variable

[dje at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98139

--- Comment #2 from David Edelsohn <dje at gcc dot gnu.org> ---
I bootstrap GCC on AIX with, and the instructions in the CompileFarm wiki
recommend, --disable-werror.

If that currently is the only problem, we're lucky.  I don't know that this
hack is better.  Shrug.