Implements #24024 for mpfr.

This one is slightly non-trivial especially in how it uses multiple configure calls. However, my local experiments show that it's just fine to use sdh_configure there all the same (though it isn't strictly necessary either).

Depends on #23733

Component: build

Keywords: destdir mpfr

Author: Erik Bray

Branch/Commit: faec643

Reviewer: Julian Rüth

Issue created by migration from https://trac.sagemath.org/ticket/25045