math/mpfi: make fetchable again with a silent update

MASTER_SITES moved to ENS Lyon.

Meanwhile the tarball has been rerolled:

• many auto* stuff: configure is now pre-generated;
• mpfi.pc is available
• change tests

but also some code has been modified.

Full diff available at https://people.freebsd.org/~thierry/mpfi-1.5.4.diff

PR: 293803
Reported by: Daniel Engberg