Update to 2.7.0. Add --with-extra-cflags=-I${PREFIX}/include
so configure finds pcap/sll.h. Add a rc.d script. Fix the path
to the config directory in upload-prep.pl or else it silently
exits without doing anything when it doesn't find any configs.

PR: 230661
Reviewed by: ler (mentor)
Approved by: Leo Vandewoestijn (maintainer), ler (mentor)
Differential Revision: https://reviews.freebsd.org/D16925