+AC_ARG_ENABLE(sendfds, AS_HELP_STRING([--disable-sendfds], [Support FD passing (default: auto)]),
+ [sendfds=$enableval], [sendfds=auto])
+
+case x$sendfds in
+xauto)
+ AC_SEARCH_LIBS(sendmsg, socket, [sendfds="yes"], [sendfds="no"])
+ ;;
+esac
+
+# XPG4v2/UNIX95 added msg_control - check to see if we need to define
+# _XOPEN_SOURCE to get it (such as on Solaris)
+AC_CHECK_MEMBER([struct msghdr.msg_control], [], [],
+ [
+AC_INCLUDES_DEFAULT
+#include <sys/socket.h>
+ ])
+# First try for Solaris in C99 compliant mode, which requires XPG6/UNIX03
+if test "x$ac_cv_member_struct_msghdr_msg_control" = xno; then
+ unset ac_cv_member_struct_msghdr_msg_control
+ AC_MSG_NOTICE([trying again with _XOPEN_SOURCE=600])
+ AC_CHECK_MEMBER([struct msghdr.msg_control],
+ [AC_DEFINE([_XOPEN_SOURCE], [600],
+ [Defined if needed to expose struct msghdr.msg_control])
+ ], [], [
+#define _XOPEN_SOURCE 600
+AC_INCLUDES_DEFAULT
+#include <sys/socket.h>
+ ])
+fi
+# If that didn't work, fall back to XPG5/UNIX98 with C89
+if test "x$ac_cv_member_struct_msghdr_msg_control" = xno; then
+ unset ac_cv_member_struct_msghdr_msg_control
+ AC_MSG_NOTICE([trying again with _XOPEN_SOURCE=500])
+ AC_CHECK_MEMBER([struct msghdr.msg_control],
+ [AC_DEFINE([_XOPEN_SOURCE], [500],
+ [Defined if needed to expose struct msghdr.msg_control])
+ ], [sendfds="no"], [
+#define _XOPEN_SOURCE 500
+AC_INCLUDES_DEFAULT
+#include <sys/socket.h>
+ ])
+fi
+
+case x$sendfds in
+xyes)
+ AC_DEFINE([HAVE_SENDMSG],1,[Define if your platform supports sendmsg])
+ ;;
+esac
+