diff -r 517655a528fe -r c1a27fce2076 lib/scripts/ghc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/scripts/ghc	Thu Nov 08 16:18:12 2018 +0100
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+#
+# Author: Makarius
+#
+# Invoke ghc via "stack".
+
+if [ -d "$ISABELLE_STACK_ROOT" ]; then
+  isabelle_stack ghc -- "$@"
+else
+  echo "Cannot execute ghc: missing Isabelle GHC setup" >&2
+  exit 127
+fi