When run as a script, don't pass a fake __main__ dictionary; use the
real one.
diff --git a/Lib/pdb.py b/Lib/pdb.py
index de769bb..fae6b2c 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -893,4 +893,4 @@
 	# Insert script directory in front of module search path
 	sys.path.insert(0, os.path.dirname(filename))
 
-	run('execfile(' + `filename` + ')', {'__name__': '__main__'})
+	run('execfile(' + `filename` + ')')