$OpenBSD: patch-boost_asio_detail_config_hpp,v 1.4 2021/02/01 12:00:51 rsadowski Exp $

Use _POSIX_VERSION to detect support for MSG_NOSIGNAL.

Index: boost/asio/detail/config.hpp
--- boost/asio/detail/config.hpp.orig
+++ boost/asio/detail/config.hpp
@@ -1475,4 +1475,15 @@
 # endif // defined(__clang__)
 #endif // !defined(BOOST_ASIO_HAS_CO_AWAIT)
 
+// Kernel support for MSG_NOSIGNAL.
+#if !defined(BOOST_ASIO_HAS_MSG_NOSIGNAL)
+# if defined(__linux__)
+#  define BOOST_ASIO_HAS_MSG_NOSIGNAL 1
+# elif defined(_POSIX_VERSION)
+#  if (_POSIX_VERSION >= 200809L)
+#   define BOOST_ASIO_HAS_MSG_NOSIGNAL 1
+#  endif // _POSIX_VERSION >= 200809L
+# endif // defined(_POSIX_VERSION)
+#endif // !defined(BOOST_ASIO_HAS_MSG_NOSIGNAL)
+
 #endif // BOOST_ASIO_DETAIL_CONFIG_HPP
