Fix use of 'file' as a variable name.
    (I've tested the fixes, but please proofread anyway.)
diff --git a/Tools/scripts/ifdef.py b/Tools/scripts/ifdef.py
index c0c1459..15777f4 100755
--- a/Tools/scripts/ifdef.py
+++ b/Tools/scripts/ifdef.py
@@ -42,11 +42,11 @@
             undefs.append(a)
     if not args:
         args = ['-']
-    for file in args:
-        if file == '-':
+    for filename in args:
+        if filename == '-':
             process(sys.stdin, sys.stdout)
         else:
-            f = open(file, 'r')
+            f = open(filename, 'r')
             process(f, sys.stdout)
             f.close()