[PATCH] Enforce GMP/MPFR version requires and fix fortran/28276,27021

[DJ Delorie]

> 4) Over time, reviewers get tired of running into #2 and #3, and
> start doing reviews in a more timely fashion.

More likely, 4) reviewers get tired of running into #2 and #3, and
step down, figuring nobody wants them to review patches anyway.  But
toplevel patches can't get applied without notice; I have scripts that
watch them as multiple repositories need to be coordinated.  If you're
not careful, a mis-applied patch may get merged out of existance.

I don't like not having my patches reviewed (and I'm a maintainer) but
I understand that it's *my* reponsibility to keep track of unreviewed
patches.  Maintainers are not all-knowing.  It's OK to bug us if a
patch goes unloved for a few weeks, we probably just missed it the
first time around.

This thread is kind of silly, since I approved this patch this morning
(it was buried in a fortran thread, and no, I don't read *every*
gcc-patches email), even though Steve pinged me - personally - TWICE
today, once even after I approved it.