CYG_MAX_PATH.
* fhandler_tty.cc (fhandler_pty_master::ptsname): Set buffer size to
TTY_NAME_MAX.
* syscalls.cc (ttyname): Eliminate the `+ 1' from the name buffer size
since TTY_NAME_MAX already counts the trailing NUL.
* libc/bsdlib.cc (openpty): Set pts buffer size to TTY_NAME_MAX.