SF feature request #686323: Minor array module enhancements

array.extend() now accepts iterable arguments implements as a series
of appends.  Besides being a user convenience and matching the behavior
for lists, this the saves memory and cycles that would be used to
create a temporary array object.

Lib/test/test_array.py

@@ -592,6 +592,13 @@ class BaseTest(unittest.TestCase):
         b = array.array(self.badtypecode())
         self.assertRaises(TypeError, a.extend, b)
 
+        a = array.array(self.typecode, self.example)
+        a.extend(self.example[::-1])
+        self.assertEqual(
+            a,
+            array.array(self.typecode, self.example+self.example[::-1])
+        )
+
     def test_coveritertraverse(self):
         try:
             import gc