Force zlib.crc32 and zlib.adler32 to return a signed integer on all platforms
regardless of the native sizeof(long) used in the integer object.

This somewhat odd behavior of returning a signed is maintained in 2.x for
compatibility reasons of always returning an integer rather than a long object.

Fixes Issue1202 for Python 2.6
diff --git a/Misc/NEWS b/Misc/NEWS
index 47f8df1..1963ad5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -27,6 +27,10 @@
 Library
 -------
 
+- Issue #1202: zlib.crc32 and zlib.adler32 no longer return different values
+  on 32-bit vs. 64-bit python interpreters.  Both were correct, but they now
+  both return a signed integer object for consistency.
+
 - Issue #1158: add %f format (fractions of a second represented as
   microseconds) to datetime objects.  Understood by both strptime and
   strftime.