Received packets treatment has some difference regarding if this is the first one or not of the encapsulating datagram. Previously, this was set via a function argument. Simplify this by defining a new Rx packet flag named QUIC_FL_RX_PACKET_DGRAM_FIRST. This change does not have functional impact. It will simplify API when qc_lstnr_pkt_rcv() is broken into several functions : their number of arguments will be reduced thanks to this patch. This should be backported up to 2.6. (cherry picked from commit deb7c87f5525d5645dd7c94fb187603edbb8d27a) Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>