An update for cppo came up today, and after trying to install it, it goes through the building process fine but comes up with this error:

# error: executing gringo failed (No such file or directory)
# error: gringo returned with non-zero exit status

[ERROR] External solver failure, please fix your installation and check
        /tmp/pamac-build-mdub/jbuilder/src/.opam/config and variable $OPAMEXTERNALSOLVER.
        You may also retry with option --use-internal-solver
[ERROR] Initialisation failed
OpamGlobals.Exit(66)
==> ERROR: A failure occurred in package().
    Aborting...


I’ve cleaned the version cache and it didn’t help. Any clue as to whats going on would be great.