* io.c (rb_io_set_nonblock): new function.
  (io_getpartial): nonblocking read support.
  (io_read_nonblock): new method: IO#read_nonblock.
  (io_write_nonblock): new method: IO#write_nonblock.

* ext/socket/socket.c
  (sock_connect_nonblock): new method: Socket#connect_nonblock.
  (sock_accept_nonblock): new method: Socket#accept_nonblock.
  (sock_recvfrom_nonblock): new method: Socket#recvfrom_nonblock.

  [ruby-core:7917]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10176 b2dd03c8-39d4-4d8f-98ff-823fe69b080e