diff --git a/hacking/env-setup b/hacking/env-setup
index 9b9a529d13a..16baa9b1b75 100644
--- a/hacking/env-setup
+++ b/hacking/env-setup
@@ -16,7 +16,7 @@ if [ -n "$BASH_SOURCE" ] ; then
     HACKING_DIR=$(dirname "$BASH_SOURCE")
 elif [ $(basename -- "$0") = "env-setup" ]; then
     HACKING_DIR=$(dirname "$0")
-elif [ -n "$KSH_VERSION" ]; then
+elif [ -n "$KSH_VERSION" ] && echo $KSH_VERSION | grep -qv '^@(#)PD KSH'; then
     HACKING_DIR=$(dirname "${.sh.file}")
 else
     HACKING_DIR="$PWD/hacking"