* net.cc (fdsock): Raise send/recv buffer sizes for x86_64.  Extend
	comment.
	(cygwin_setsockopt): Fix condition and syscall_printf.
	* fhandler_tty.cc (fhandler_pty_slave::write): Change type of towrite to
	ssize_t.
	(fhandler_pty_slave::read): Ditto for totalread.
Merge branch 'cygwin64' into msys2-64-dev