diff --git a/include/boost/config/compiler/gcc.hpp b/include/boost/config/compiler/gcc.hpp
index cb3c9cfd..73d8bba6 100644
--- a/include/boost/config/compiler/gcc.hpp
+++ b/include/boost/config/compiler/gcc.hpp
@@ -36,6 +36,13 @@
 #  define BOOST_NO_INTRINSIC_WCHAR_T
 #endif
 
+//
+// Threading support:
+// Turn this on unconditionally here, it will get turned off again later
+// if no threading API is detected.
+//
+#define BOOST_HAS_THREADS
+
 #define BOOST_COMPILER "GNU C++ version " BOOST_STRINGIZE(__GNUC__) "." BOOST_STRINGIZE(__GNUC_MINOR__)
 
 //
diff --git a/include/boost/config/platform/cygwin.hpp b/include/boost/config/platform/cygwin.hpp
index 9ba1b629..b5749511 100644
--- a/include/boost/config/platform/cygwin.hpp
+++ b/include/boost/config/platform/cygwin.hpp
@@ -12,5 +12,17 @@
 #define BOOST_NO_CWCHAR
 #define BOOST_NO_SWPRINTF
 
+//
+// Threading API:
+// See if we have POSIX threads, if we do use them, otherwise
+// revert to native Win threads.
+#include <unistd.h>
+#if if defined(_POSIX_THREADS) && (_POSIX_THREADS+0 >= 0) && !defined(BOOST_HAS_WINTHREADS)
+#  define BOOST_HAS_PTHREADS
+#  define BOOST_HAS_SCHED_YIELD
+#else
+#  define NOOST_HAS_WINTHREADS
+#endif
+
  
 
diff --git a/include/boost/config/posix_features.hpp b/include/boost/config/posix_features.hpp
index 7a4a4591..fc4271b4 100644
--- a/include/boost/config/posix_features.hpp
+++ b/include/boost/config/posix_features.hpp
@@ -30,4 +30,36 @@
 #        define BOOST_HAS_PTHREADS
 #     endif
 
+      // BOOST_HAS_NANOSLEEP:
+      // This is predicated on _POSIX_TIMERS:
+#     if defined(_POSIX_TIMERS) && (_POSIX_TIMERS+0 >= 0)
+#        define BOOST_HAS_NANOSLEEP
+#     endif
+
+      // BOOST_HAS_SCHED_YIELD:
+      // This is predicated on _POSIX_PRIORITY_SCHEDULING or
+      // on _POSIX_THREAD_PRIORITY_SCHEDULING.
+#     if defined(_POSIX_PRIORITY_SCHEDULING) && (_POSIX_PRIORITY_SCHEDULING+0 > 0)
+#        define BOOST_HAS_SCHED_YIELD
+#     endif
+#     if defined(_POSIX_THREAD_PRIORITY_SCHEDULING) && (_POSIX_THREAD_PRIORITY_SCHEDULING+0 > 0)
+#        define BOOST_HAS_SCHED_YIELD
+#     endif
+
+      // BOOST_HAS_GETTIMEOFDAY:
+      // BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE:
+      // These are predicated on _XOPEN_VERSION, and appears to be first released
+      // in issue 4, version 2 (_XOPEN_VERSION > 500).
+#     if defined(_XOPEN_VERSION) && (_XOPEN_VERSION+0 > 500)
+#        define BOOST_HAS_GETTIMEOFDAY
+#        define BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE
+#     endif
+
+      // BOOST_HAS_CLOCK_GETTIME:
+      // This is predicated on _POSIX_TIMERS.
+#     if defined(_POSIX_TIMERS) && (_POSIX_TIMERS+0 > 0)
+#        define BOOST_HAS_CLOCK_GETTIME
+#     endif
+
+
 #  endif