[Bug go/68931] gccgo fails to build using MUSL libc

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68931

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
I don't understand your patch, because I don't understand where CONFIG_USE_MUSL
gets set.

It also seems like the wrong approach.  The basic goal of configure tests is to
test for features, not systems.  mksysinfo.sh already works that way.  What
fails without this patch?