--- /dev/null
+dnl @synopsis LIB_SOCKET_NSL
+dnl
+dnl This macro figures out what libraries are required on this platform
+dnl to link sockets programs.
+dnl
+dnl The common cases are not to need any extra libraries, or to need
+dnl -lsocket and -lnsl. We need to avoid linking with libnsl unless we
+dnl need it, though, since on some OSes where it isn't necessary it
+dnl will totally break networking. Unisys also includes gethostbyname()
+dnl in libsocket but needs libnsl for socket().
+dnl
+dnl @category Misc
+dnl @author Russ Allbery <rra@stanford.edu>
+dnl @author Stepan Kasal <kasal@ucw.cz>
+dnl @author Warren Young <warren@etr-usa.com>
+dnl @version 2005-09-06
+
+AC_DEFUN([LIB_SOCKET_NSL],
+[
+ AC_SEARCH_LIBS([gethostbyname], [nsl])
+ AC_SEARCH_LIBS([socket], [socket], [], [
+ AC_CHECK_LIB([socket], [socket], [LIBS="-lsocket -lnsl $LIBS"],
+ [], [-lnsl])])
+])