Need a version check/constraint for z3

[Kakadu]

I tried to build z3overlay and z3 opam package with ocaml bindings itself on my Ubuntu (which has libz3-dev 4.4.1) and got a few linking errors (when running helloworld) about missing Z3_fpa_get_numeral_sign_bv. When I makeinstalled latest z3 and ocaml bindings from git, the error has been gone.

It seems that we need a version constraint or even whole conf-z3 package to prevent users from installing too fresh OCaml binding for too old system-wide z3... Or maybe an opam package which will install z3 itself to the current switch

P.S. I also realized that the version of z3 bindings is not synchronized with the directory name here (4.6 vs 3.4.6)

@c-cube

[Kakadu]

Got a solution in the IRC.