use different command in check_permissions.sh to suppot macosx

util/check_permissions.sh

@@ -7,12 +7,12 @@ path=$PWD
 
 # Check upstream hierarchy of current directory
 while [ $path != '/' ]; do
-  o_perms=$(stat $path --format="%A" | grep -o "...$")
-  if [ ${o_perms:0:1} != 'r' ]; then
+  o_perms=$(ls -ld $path | awk '{print $1}' | grep -oE "[r-][w-][x-].?$")
+  if [ "${o_perms:0:1}" != 'r' ]; then
     echo "Path $path is not readable by non-owners; set o+r" 1>&2
     iret=1
   fi
-  if [ ${o_perms:2:3} != 'x' ]; then
+  if [ "${o_perms:2:3}" != 'x' ]; then
     echo "Path $path is not accessible by non-owners; set o+x" 1&>2
     iret=1
   fi