[Bug go/91692] gcc build fails with --enable-languages="go"

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91692

--- Comment #2 from Ian Lance Taylor <ian at airs dot com> ---
Thanks for the bug report.  The normal case when configuring GCC is to create a
new empty directory and run SRCDIR/configure in that directory, as documented
at https://gcc.gnu.org/install/configure.html.  Your suggested patch will break
that normal case.

The case of running ./configure should also work, but is rarely tested. 
Clearly there is something wrong in that case that will need to be fixed.