Index: Tools/scripts/diff.py
===================================================================
--- Tools/scripts/diff.py	(revision 77065)
+++ Tools/scripts/diff.py	(working copy)
@@ -7,7 +7,7 @@
 
 """
 
-import sys, os, time, difflib, optparse
+import sys, os, datetime, difflib, optparse
 
 def main():
 
@@ -29,8 +29,18 @@
     n = options.lines
     fromfile, tofile = args
 
-    fromdate = time.ctime(os.stat(fromfile).st_mtime)
-    todate = time.ctime(os.stat(tofile).st_mtime)
+    def isomtime(fname):
+        dt = datetime.datetime.fromtimestamp( os.stat(fname).st_mtime )
+        # Make RFC 3339 compliant timestamp
+        if dt.tzinfo is None:
+            suffix = "-00:00"
+        else:
+            suffix = dt.strftime("%z")
+            suffix = suffix[:-2] + ":" + suffix[-2:]
+        return dt.strftime("%Y-%m-%dT%H:%M:%S") + suffix
+
+    fromdate = isomtime(fromfile)
+    todate = isomtime(fromfile)
     fromlines = open(fromfile, 'U').readlines()
     tolines = open(tofile, 'U').readlines()