While there, keep error messages in a single line even if they are
longer than 80 characters.

While there, remove some trailing whitespaces.

For now don't allocate memory, so we don't have to free it.
This will not work for all future socket options, but it simplifies
things for now.

This patch allows to use sctp_assoc_value in getsockopt and also supports
numeric constants as values.

add last corrections from diff and fix sctp_rtoinfo for setsockopt with ellipsis as type for all values