ERROR while compiling conf-gmp-paths.1

[vbgl]

While trying to build dependencies of apron using opam, ez-conf-lib reports to have found gmp library in an empty path and ends with an error:

# checking compilation with gcc: working
# looking for gmp without prefix
# include gmp.h: found in /nix/store/1fszsmhmlhbi4yzl2wgi08cfw0dng7pq-gmp-with-cxx-6.3.0-dev/include
# library gmp: found in 
# error: unable to locate gmp library

Full log: https://gitlab.com/jasmin-lang/jasmin/-/jobs/6143092137