diff --git a/winsup/autogen.sh b/winsup/autogen.sh
index 2dae1ae37..22036d976 100755
--- a/winsup/autogen.sh
+++ b/winsup/autogen.sh
@@ -1,4 +1,6 @@
+#!/bin/sh
 set -e
+cd $(dirname $0)
 /usr/bin/aclocal --force
 /usr/bin/autoconf -f
 /usr/bin/automake -ac