more robust: allow empty root (e.g. via symlink);
#!/usr/bin/env bash
#
# Author: Makarius
#
# Invoke ocamlc via "opam".
if [ -e "$ISABELLE_OPAM_ROOT/config" ]
then
isabelle_opam config exec --switch "$ISABELLE_OCAML_VERSION" -- ocamlc "$@"
else
echo "Cannot execute ocamlc: missing Isabelle OCaml setup" >&2
exit 127
fi