https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66809
--- Comment #2 from James Ballantine <j.ballantine at gmail dot com> --- If you look at attachment, you will see that he options for "--with-gmp=/usr/local/add-on/gmp --with-mpc=/usr/local/add-on/mpc --with-mpfr=/usr/local/add-on/mpfr" were set
