Use git diff style to show file permission changes.
--- a/.hgrc Thu Sep 08 17:15:27 2011 +0300
+++ b/.hgrc Sat Sep 17 01:28:45 2011 +0300
@@ -12,6 +12,7 @@
log = -v -f
incoming = -v
outgoing = -v
+diff = --git
[merge-tools]
emacs.args = -q --eval "(ediff-merge-with-ancestor \"$local\" \"$other\" \"$base\" nil \"$output\")"