propagate ISABELLE_CLASSPATH;

--- a/Admin/lib/Tools/makedist	Thu Sep 12 14:06:08 2013 +0200
+++ b/Admin/lib/Tools/makedist	Thu Sep 12 14:10:45 2013 +0200
@@ -168,6 +168,8 @@
 find . "(" -name \*.thy -o -name \*.ML -o -name \*.scala ")" -perm +111 -print | xargs chmod -f -x
 find . -print | xargs chmod -f u+rw
 
+export CLASSPATH="$ISABELLE_CLASSPATH"
+
 ./bin/isabelle env ISABELLE_SCALA_BUILD_OPTIONS="$ISABELLE_SCALA_BUILD_OPTIONS -optimise" \
   ./Admin/build all || fail "Failed to build distribution"