Index: boost/config/stdlib/libstdcpp3.hpp
===================================================================
--- boost/config/stdlib/libstdcpp3.hpp.orig 2012-01-14 19:15:34.957877838 +0100
+++ boost/config/stdlib/libstdcpp3.hpp 2012-01-14 19:19:09.660901373 +0100
@@ -34,7 +34,8 @@
#ifdef __GLIBCXX__ // gcc 3.4 and greater:
# if defined(_GLIBCXX_HAVE_GTHR_DEFAULT) \
|| defined(_GLIBCXX__PTHREADS) \
- || defined(_GLIBCXX_HAS_GTHREADS)
+ || defined(_GLIBCXX_HAS_GTHREADS) \
+ || defined(_WIN32)
//
// If the std lib has thread support turned on, then turn it on in Boost
// as well. We do this because some gcc-3.4 std lib headers define _REENTANT