In the span of one week, both gmplib.org and multiprecision.org,
respective home of gmp and mpc have gone down. The latter is still down.
It turns out that all versions of gmp and mpfr we need are mirrored on
ftp.gnu.org, so we can just use that instead. For mpc, versions > 1.0
are on ftp.gnu.org, but not earlier versions.
The one mpc version <= 1.0 we do need is 0.8.2, and a copy of the exact
same archive, as per its sha256, which we're already checking per the
gcc build scripts, can be found on snapshot.debian.org. We lose gpg
validation on the way, but since we're already checking the sha256,
that's a fine tradeoff.
At least this unblocks changes to toolchains until multiprecision.org
comes back online.
--HG--
extra : rebase_source : f2bc67f8757655d99bfd9735b80d7205f7bfe47b
e4ed02a860