socket: Change return types of link_socket_write* to ssize_t

socket: Change return types of link_socket_write* to ssize_t

This is the actual return value of send/sendto/sendmsg.
We will leave it to the single caller of link_socket_write()
to decide how to map that to the int buffer world. For now
just cast it explicitly.

Change-Id: I7852c06d331326c1dbab7b642254c0c00d4cebb8
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20240918204844.2820-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg29323.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>