Index: system_clocks.hpp
===================================================================
--- system_clocks.hpp	(revision 78572)
+++ system_clocks.hpp	(working copy)
@@ -31,7 +31,6 @@
 TODO:
 
   * Fully implement error handling, with test cases.
-  * Use boost::throw_exception. (Currently not used because of an issue with Intel 11.0.)
   * Consider issues raised by Michael Marcin:
 
     > In the past I've seen QueryPerformanceCounter give incorrect results,
@@ -70,6 +69,12 @@
 
 #include <ctime>
 
+# if defined( BOOST_CHRONO_POSIX_API )
+#   if ! defined(CLOCK_REALTIME)
+#     error <time.h> does not supply CLOCK_REALTIME
+#   endif
+# endif
+
 #ifdef BOOST_CHRONO_WINDOWS_API
 // The system_clock tick is 100 nanoseconds
 # define BOOST_SYSTEM_CLOCK_DURATION boost::chrono::duration<boost::int_least64_t, ratio<BOOST_RATIO_INTMAX_C(1), BOOST_RATIO_INTMAX_C(10000000)> >
Index: config.hpp
===================================================================
--- config.hpp	(revision 78572)
+++ config.hpp	(working copy)
@@ -70,12 +70,8 @@
 # if defined( BOOST_CHRONO_POSIX_API )
 #   define BOOST_CHRONO_HAS_PROCESS_CLOCKS
 #   include <time.h>  //to check for CLOCK_REALTIME and CLOCK_MONOTONIC and _POSIX_THREAD_CPUTIME
-#   if defined(CLOCK_REALTIME)
-#     if defined(CLOCK_MONOTONIC)
-#        define BOOST_CHRONO_HAS_CLOCK_STEADY
-#     endif
-#   else
-#     error <time.h> does not supply CLOCK_REALTIME
+#   if defined(CLOCK_MONOTONIC)
+#      define BOOST_CHRONO_HAS_CLOCK_STEADY
 #   endif
 #   if defined(_POSIX_THREAD_CPUTIME) && !defined(BOOST_DISABLE_THREADS)
 #     define BOOST_CHRONO_HAS_THREAD_CLOCK