Issue #15204: Deprecated the 'U' mode in file-like objects.
diff --git a/Tools/scripts/ndiff.py b/Tools/scripts/ndiff.py
index 2422091..c6d09b8 100755
--- a/Tools/scripts/ndiff.py
+++ b/Tools/scripts/ndiff.py
@@ -60,7 +60,7 @@
 # couldn't be opened
 def fopen(fname):
     try:
-        return open(fname, 'U')
+        return open(fname)
     except IOError as detail:
         return fail("couldn't open " + fname + ": " + str(detail))