updates to fix serialization regression caused by changes to the serialization lib -- macros must now be outside namespace

[SVN r28457]

libs/date_time

@@ -1 +1 @@
-Subproject commit d13c4ec9f3f09ec1342f08a8c74c8ece9aee41f4
+Subproject commit 9992b00c59bfe7330f61c1b37f6af23912f50aa2