before closing them.
(make_pty_info): Use resource_init(). Bugfix: Don't initialize
alive to 0; that would cause the pty to be dropped from resource
lists where it is inserted. Instead, set the fd:s to -1 to
indicate that no pty has been allocated yet.
(pty_allocate): Set fd:s to -1 if they are closed.

Rev: src/server_pty.c:1.18