Issue #12549: Correct test_platform to not fail when OS X returns 'x86_64'
as the processor type on some Mac systems.  Also fix NameError in fallback
_mac_ver_gestalt function.  And remove out-of-date URL in docs.
diff --git a/Misc/NEWS b/Misc/NEWS
index b282c13..7271ef9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -101,6 +101,9 @@
 Tests
 -----
 
+- Issue #12549: Correct test_platform to not fail when OS X returns 'x86_64'
+  as the processor type on some Mac systems.
+
 - Skip network tests when getaddrinfo() returns EAI_AGAIN, meaning a temporary
   failure in name resolution.