Index: boost/config/suffix.hpp
===================================================================
--- boost/config/suffix.hpp	(revision 75283)
+++ boost/config/suffix.hpp	(working copy)
@@ -253,7 +253,8 @@
 // from here then add to the appropriate compiler section):
 //
 #if (defined(__MT__) || defined(_MT) || defined(_REENTRANT) \
-    || defined(_PTHREADS) || defined(__APPLE__) || defined(__DragonFly__)) \
+    || defined(_PTHREADS) || defined(_POSIX_THREADS) \
+    || defined(__APPLE__) || defined(__DragonFly__)) \
     && !defined(BOOST_HAS_THREADS)
 #  define BOOST_HAS_THREADS
 #endif