initial handshake on AF_LOCAL sockets.
* fhandler.h (class fhandler_socket): Add no_getpeereid status flag.
(fhandler_socket::af_local_set_no_getpeereid): New prototype.
* fhandler_socket.cc (fhandler_socket::af_local_connect): Skip handshake
if no_getpeereid is set. Add debug output.
(fhandler_socket::af_local_accept): Likewise.
(fhandler_socket::af_local_set_no_getpeereid): New function.
(fhandler_socket::af_local_copy): Copy no_getpeereid.
(fhandler_socket::getpeereid): Fail if no_getpeereid is set.
* net.cc (cygwin_setsockopt): Add SO_PEERCRED for AF_LOCAL/SOCK_STREAM
sockets. Add comment to explain why we need it.
* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.