Added new macros def's that are needed by the various additions that have been added to Boost.Config.

[SVN r39183]

libs/config

@@ -1 +1 @@
-Subproject commit 6ed14ed5e14fff434ffe778fd165a7b370e0234d
+Subproject commit 668757a21630b69f120cc724738480cc7658420e