* cygwin.din (getpeereid): Export.

	* cygwin.din (getpeereid): Export.
	* fhandler.h (class fhandler_socket): Add pipe and id members to
	exchange eid credentials for AF_LOCAL sockets.
	(eid_pipe_name): Declare new method.
	(getpeereid): Ditto.
	* fhandler_socket.cc (fhandler_socket::eid_pipe_name): New method.
	(fhandler_socket::fhandler_socket): Initialize sec_pipe.
	(fhandler_socket::connect): Exchange eid credentials with accepting
	socket process.
	(fhandler_socket::listen): Prepare eid credential transaction.
	(fhandler_socket::accept): Exchange eid credentials with connecting
	socket process.
	(fhandler_socket::close): Close eid credentials pipe if open.
	(fhandler_socket::getpeereid): New method.
	* net.cc (cygwin_getsockopt): Add SO_PEERCRED handling.
	(getpeereid): New function.
	* include/asm/socket.h (SO_PEERCRED): Define.
	* include/cygwin/socket.h (struct ucred): Define new type.
	* include/cygwin/version.h: Bump API minor version.