rollback BOOST_THREAD_PATCH.

src/pthread/once.cpp

@@ -42,6 +42,7 @@ namespace boost
                 }
             }
 
+#if defined BOOST_THREAD_PATCH
             const pthread_once_t pthread_once_init_value=PTHREAD_ONCE_INIT;
             struct BOOST_THREAD_DECL delete_epoch_tss_key_on_dlclose_t
             {
@@ -57,6 +58,7 @@ namespace boost
                 }
             };
             delete_epoch_tss_key_on_dlclose_t delete_epoch_tss_key_on_dlclose;
+#endif
         }
 
         uintmax_atomic_t& get_once_per_thread_epoch()