config/ax_lib_socket_nsl.m4

# ===========================================================================
#    https://www.gnu.org/software/autoconf-archive/ax_lib_socket_nsl.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_LIB_SOCKET_NSL
#
# DESCRIPTION
#
#   This macro figures out what libraries are required on this platform to
#   link sockets programs.
#
#   The common cases are not to need any extra libraries, or to need
#   -lsocket and -lnsl. We need to avoid linking with libnsl unless we need
#   it, though, since on some OSes where it isn't necessary it will totally
#   break networking. Unisys also includes gethostbyname() in libsocket but
#   needs libnsl for socket().
#
# LICENSE
#
#   Copyright (c) 2008 Russ Allbery <rra@stanford.edu>
#   Copyright (c) 2008 Stepan Kasal <kasal@ucw.cz>
#   Copyright (c) 2008 Warren Young <warren@etr-usa.com>
#
#   Copying and distribution of this file, with or without modification, are
#   permitted in any medium without royalty provided the copyright notice
#   and this notice are preserved. This file is offered as-is, without any
#   warranty.

#serial 7

AU_ALIAS([LIB_SOCKET_NSL], [AX_LIB_SOCKET_NSL])
AC_DEFUN([AX_LIB_SOCKET_NSL],
[
	AC_SEARCH_LIBS([gethostbyname], [nsl])
	AC_SEARCH_LIBS([socket], [socket], [], [
		AC_CHECK_LIB([socket], [socket], [LIBS="-lsocket -lnsl $LIBS"],
		[], [-lnsl])])
])