examples: cast arguments of connect(2)

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Buffer: add ssh_buffer_(un)pack()

That function permits chaining of buffer values to minimize buffer handling
in packet sending code.

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
tests: test for ssh_buffer_(un)pack

Reviewed-by: Andreas Schneider <asn@samba.org>
buffer: adapt auth.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
buffer: adapt kex.c to new ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffer: adapt dh.c to new ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt channels.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt client.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt curve25519.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt gssapi.c to ssh_buffer_(un)pack()
buffers: adapt messages.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt packet.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt ecdh.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt pcap.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt server.c to ssh_buffer_(un)pack()

Signed-off-by: Andreas Schneider <asn@samba.org>
buffers: adapt session.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt sftp.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffers: adapt sftpserver.c to ssh_buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>
buffer: add a hidden canary to detect format errors

Reviewed-by: Andreas Schneider <asn@samba.org>
tests: test the canary feature in buffer_(un)pack()

Reviewed-by: Andreas Schneider <asn@samba.org>