zarith fails to install on Rocky Linux 8

[lexbailey]

This might also be a problem on other distros, I'm not sure.

opam install zarith results in an error from the configure script in the zarith package.

It says that it is unable to find the gmp library, even when it is installed.

The configure script attempts to find it via a pkg-config file first, wihch fails since there is not one available for gmp on Rocky Linux 8. Then it tries to compile and link an empty program against gmp, which fails with other unrelated linker issues.

the gmp and gmp-devel packages are installed on the base system from the normal package manager (dnf)

[ERROR] The compilation of zarith.1.14 failed at "./configure".

#=== ERROR while compiling zarith.1.14 ========================================#
# context 2.1.3 | linux/x86_64 | ocaml.5.2.1 | https://opam.ocaml.org#f708af850343b2bc3bfd2a069aa8c836d46c59f9
# path ~/.opam/default/.opam-switch/build/zarith.1.14
# command ~/.opam/opam-init/hooks/sandbox.sh build ./configure
# exit-code 2
# env-file ~/.opam/log/zarith-562501-52f62a.env
# output-file ~/.opam/log/zarith-562501-52f62a.out
### output ###
# [...]
# binary ocamldoc: found in /home/codasip.com/lex.bailey/.opam/default/bin
# binary gcc: found in /nix/store/4apajimszc47rxwcpvc3g3rj2icinl71-gcc-wrapper-13.3.0/bin
# binary ocamlopt: found in /home/codasip.com/lex.bailey/.opam/default/bin
# checking compilation with ocamlc -frandom-seed=4nbi99dk6l -isystem /nix/store/v34vi1nqnkdbk8lydckhcn9zar100pmf-gettext-0.21.1/include -isystem /nix/store/zv1kaq7f1q20x62kbjv6pfjygw5jmwl6-python3-3.12.7/include -isystem /nix/store/v34vi1nqnkdbk8lydckhcn9zar100pmf-gettext-0.21.1/include -isystem /nix/store/zv1kaq7f1q20x62kbjv6pfjygw5jmwl6-python3-3.12.7/include -frandom-seed=d2jglgglrm -isystem[...]
# include caml/mlvalues.h: found
# library dynlink.cmxa: found
# binary ocamlfind: found in /home/codasip.com/lex.bailey/.opam/default/bin
# OCaml's word size is 64
# include gmp.h: found
# library gmp: not found
# include mpir.h: not found
# cannot find GMP nor MPIR



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build zarith 1.14
└─
╶─ No changes have been performed

edit: fixed formatting issue where URLs were pasted in markdown syntax

[lexbailey]

Upon further investigation, there is actually another factor here. I was using opam from nix, and it appears that there is some issue relating to the nix version of opam that makes this not work, I switched to the native version and it works fine there.
I'm not sure if this is an opam package bug or a nix package bug.