diff -r 678e1c9eb009 -r 842fc354c031 lib/scripts/getfunctions
--- a/lib/scripts/getfunctions	Thu Jul 15 17:33:06 2021 +0200
+++ b/lib/scripts/getfunctions	Thu Jul 15 18:18:07 2021 +0200
@@ -106,7 +106,7 @@
   do
     if [ -z "$ISABELLE_CLASSPATH" ]; then
       ISABELLE_CLASSPATH="$X"
-    else
+    elif [ -n "$X" ]; then
       ISABELLE_CLASSPATH="$ISABELLE_CLASSPATH:$X"
     fi
   done