RTP out: robustify send error handling
RTP out: robustify send error handling

For error other than congestion (EAGAIN, EWOULDBLOCK, ENOBUFS, ENOMEM),
check the socket type. If the socket is a datagram, retry. Otherwise,
the socket is connection-oriented and we assume the connection broke,
close it.

vlc-mirror/vlc-2.1,vlc-mirror/vlc,shyamalschandra/vlc,vlc-mirror/vlc,krichter722/vlc,xkfz007/vlc,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.2,krichter722/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,krichter722/vlc,krichter722/vlc,shyamalschandra/vlc,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,jomanmuk/vlc-2.2,vlc-mirror/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.1,krichter722/vlc,krichter722/vlc,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1