// First include <cstddef> to determine if some version of STLport is in use as the std lib
// (do not rely on this header being included since users can short-circuit this header
// if they know whose std lib they are using.)
-#include <cstddef>
+#ifdef __cplusplus
+# include <cstddef>
+#else
+# include <stddef.h>
+#endif
#if defined(__SGI_STL_PORT) || defined(_STLPORT_VERSION)
// STLPort library; this _must_ come first, otherwise since
// Rogue Wave library:
# define BOOST_STDLIB_CONFIG "boost/config/stdlib/roguewave.hpp"
+#elif defined(_LIBCPP_VERSION)
+// libc++
+# define BOOST_STDLIB_CONFIG "boost/config/stdlib/libcpp.hpp"
+
#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
// GNU libstdc++ 3
# define BOOST_STDLIB_CONFIG "boost/config/stdlib/libstdcpp3.hpp"