Build static binaries for releases

[Gbury]

Binaries bundled in the releases should be statically linked for ease of use (particularly on systems with odler libc, such as starexec).

Adding -cclib -static seems sufficient in some cases, but it might also be worth it to follow tis blog post detailing how to build ocaml static binaries in general : https://ocamlpro.com/blog/2021_09_02_generating_static_and_portable_executables_with_ocaml/

[bobot]

For another example: https://git.frama-c.com/pub/colibrics/-/blob/master/.gitlab-ci.yml#L53

[Gbury]

I've tried the -cclib -static option, and it doesn't work because I don't have static versions of gmp and mpfr installed (additionally it seems to be quite a not-so-good idea to try and static link the glibc, and may lead to problems down the road). More generally, it seems that to get a robust solution, it's probably better to follow the instruction from the blogpost. I'll see when I have the time to try and setup that (in the meantime, if someone is motivated to work on this, that'd also be nice, :) ).