Index: boost/chrono/chrono.hpp
===================================================================
--- boost/chrono/chrono.hpp	(revision 52554)
+++ boost/chrono/chrono.hpp	(working copy)
@@ -201,7 +201,11 @@
 
   // Clocks
   class BOOST_CHRONO_DECL system_clock;
+#ifdef BOOST_HAS_CLOCK_MONOTONIC   
   class BOOST_CHRONO_DECL monotonic_clock;
+#else
+  typedef system_clock monotonic_clock;
+#endif  
   typedef monotonic_clock high_resolution_clock;  // as permitted by [time.clock.hires]
 
 //----------------------------------------------------------------------------//
@@ -918,7 +922,7 @@
 //----------------------------------------------------------------------------//
 //      20.9.5.2 Class monotonic_clock [time.clock.monotonic]                 //
 //----------------------------------------------------------------------------//
-
+#ifdef BOOST_HAS_CLOCK_MONOTONIC   
   class BOOST_CHRONO_DECL monotonic_clock
   {
   public:
@@ -931,7 +935,7 @@
       static time_point  now();                         // throws on error
       static time_point  now(system::error_code & ec);  // never throws
   };
-
+#endif
 //----------------------------------------------------------------------------//
 //      20.9.5.3 Class high_resolution_clock [time.clock.hires]               //
 //----------------------------------------------------------------------------//
Index: libs/chrono/src/chrono.cpp
===================================================================
--- libs/chrono/src/chrono.cpp	(revision 52554)
+++ libs/chrono/src/chrono.cpp	(working copy)
@@ -256,7 +256,6 @@
   //  return time_point(duration(
   //    (static_cast<system_clock::rep>( tod.tv_sec ) * 1000000) + tod.tv_usec));
   //}
-
   #ifndef CLOCK_REALTIME
   # error <time.h> does not supply CLOCK_REALTIME
   #endif
@@ -298,6 +297,7 @@
       return time_point(duration(static_cast<system_clock::rep>(t) * 1000000000));
   }
 
+#ifdef BOOST_HAS_CLOCK_MONOTONIC   
   #ifndef CLOCK_MONOTONIC
   # error <time.h> does not supply CLOCK_MONOTONIC
   #endif
@@ -328,6 +328,7 @@
     return time_point(duration(
       static_cast<monotonic_clock::rep>( ts.tv_sec ) * 1000000000 + ts.tv_nsec));
   }
+#endif
 
 }  // namespace chrono
 }  // namespace boost
Index: libs/chrono/test/run_timer_test.cpp
===================================================================
--- libs/chrono/test/run_timer_test.cpp	(revision 52554)
+++ libs/chrono/test/run_timer_test.cpp	(working copy)
@@ -1,4 +1,4 @@
-//  boost run_timer_test.cpp  -----------------------------------------------------//
+ //  boost run_timer_test.cpp  -----------------------------------------------------//
 
 //  Copyright Beman Dawes 2006, 2008