ruby--ruby/ext/socket/extconf.rb

$LDFLAGS = "-L/usr/local/lib"
case PLATFORM
when /mswin32/
  test_func = "WSACleanup"
  have_library("wsock32", "WSACleanup")
when /cygwin32/
  test_func = "cygwin32_socket"
else
  test_func = "socket"
  have_library("socket", "socket")
  have_library("inet", "gethostbyname")
  have_library("nsl", "gethostbyname")
end
have_header("sys/un.h")
if have_func(test_func)
  have_func("hsterror")
  unless have_func("gethostname")
    have_func("uname")
  end
  if ENV["SOCKS_SERVER"]  # test if SOCKSsocket needed
    if have_library("socks", "Rconnect")
      $CFLAGS="-DSOCKS"
    end
  end
  create_makefile("socket")
end