i have boost-1.37.0-r1, when i try to emerge ogre with threading i get this: checking for main in -lboost_thread-mgw-mt... (cached) no checking for main in -lboost_thread-mgw-mt-s... (cached) no checking for main in -lboost_thread-mgw-s... (cached) no configure: error: Could not link against boost_thread-mgw-s ! note: in ogres autoconf, threading is marked as experimental.
I had similar issues. It was because of boost 1.37 did not correcly install the eselect stuff. Re-Emerging boost and doing "eselect boost set boost-1.37/default" fixed that.
Sounds like it was a bug in boost that's fixed now