 +// boilerplate code:
 +#define BOOST_HAS_UNISTD_H
 +#include <boost/config/posix_features.hpp>
-+#define BOOST_HAS_PTHREAD_YIELD
++#ifdef _NEWLIB_VERSION
++  #define BOOST_HAS_SCHED_YIELD
++  #define BOOST_HAS_PTHREADS
++#endif
 +
 +#ifndef __GNUC__
 +//

       // Oddball version of strerror_r
       const char * c_str = strerror_r( ev, bp, sz );
       return  c_str
diff --git a/tools/build/v2/tools/gcc.jam b/tools/build/v2/tools/gcc.jam
index ef90f05..da042de 100644
--- a/tools/build/v2/tools/gcc.jam

diff --git a/boost/config/platform/nacl.hpp b/boost/config/platform/nacl.hpp
new file mode 100644
index 0000000..11ce94e
--- /dev/null
+++ b/boost/config/platform/nacl.hpp
@@ -0,0 +1,82 @@
+// Copyright (c) 2013 The Native Client Authors.
+// Use, modification and distribution are subject to the
+// Boost Software License, Version 1.0. (See accompanying file
