[OE-core] mpfr & gmp updates

[Marko Lindqvist]

Objective of this patch series is to update gmp to latest versions
before fixing automake-1.13 problems. Doing it the other way around
could mean more work (porting the patch from one gmp version to next)

[PATCH 1/3] mpfr: update to upstream version 3.1.1

gmp-5.1.0 compilation fails with mpfr-3.1.0. Mpfr update fixes
thath.

[PATCH 2/3] gmp: update SRC_URI and HOMEPAGE

Use gmplib SRC_URI instead of gnu mirror one. Latter doesn't
even have latest version available. Old HOMEPAGE URL gave
"page not found".

[PATCH 3/3] gmp: update to upstream version 5.1.0



 - ML