more conservative update of Haskell stack (amending 04e54f57a869): 13.0 still lacks notable packages like "Agda" or "darcs";
#!/usr/bin/env bash
#
# Author: Makarius
#
# DESCRIPTION: invoke Scala compiler within the Isabelle environment
isabelle_admin_build jars || exit $?
isabelle_scala scalac -Dfile.encoding=UTF-8 \
-classpath "$(platform_path "$ISABELLE_CLASSPATH")" "$@"