Fill a new IOError from the message of h_errno

Used with gethostbyname.

Property definitions

socket :: socket $ IOError :: from_h_errno
	# Fill a new `IOError` from the message of `h_errno`
	#
	# Used with `gethostbyname`.
	init from_h_errno do init h_errno.to_s
lib/socket/socket.nit:498,2--501,39