lib/Tools/ghc_setup

proper treatment of root as directory;

#!/usr/bin/env bash
#
# Author: Makarius
#
# DESCRIPTION: setup Glasgow Haskell Compiler via Stack

set -e

isabelle_stack setup
isabelle_stack ghc -- --version
echo -n "$(standard_path "$(isabelle_stack path --compiler-exe)")" > "$ISABELLE_STACK_ROOT/ISABELLE_GHC_EXE-$ISABELLE_PLATFORM_FAMILY"