[Bug bootstrap/44425] configure should probe prefix for gmp/mpfr/mpc

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44425

--- Comment #3 from Eric Gallager <egallager at gcc dot gnu.org> ---
This would be done in the top-level configure script... where it looks like it
already does this for FreeBSD targets?