Fix configure options of FFLAS-FFPACK

[Flamefire]

(created using eb --new-pr)

GMP is found by using Givaro:

2.2.0 configure.ac:# Getting GMP from Givaro - AB 2014-12-12
2.5.0 configure.ac:# Looking for Givaro. We get the flags for GMP at the same time

The --with-gmp flag was removed in 2.1

The --with-givaro flag was replaced by a pkg-config check in 2.4.3/2.5.0

Caution: I also updated the old EC (2016a) which I can't build anymore.

[Flamefire]

Test report by @Flamefire
SUCCESS
Build succeeded for 1 out of 1 (1 easyconfigs in total)
n1358 - Linux RHEL 8.7 (Ootpa), x86_64, Intel(R) Xeon(R) Platinum 8470 (icelake), Python 3.8.13
See https://gist.github.com/Flamefire/03272c0acfa246f62cdc60af0de7683c for a full test report.

[Micket]

lgtm

[Micket]

Test report by @Micket
SUCCESS
Build succeeded for 3 out of 3 (1 easyconfigs in total)
vera-skylake-build - Linux Rocky Linux 8.9, x86_64, Intel Xeon Processor (Skylake, IBRS, no TSX), Python 3.6.8
See https://gist.github.com/Micket/cc1feb852b9069422ec84a579ce2daf5 for a full test report.

[Micket]

Going in, thanks @Flamefire!