For libpcap default search use AC_CHECK_LIB, AC_CHECK_HEADER. For manual libpcap spec, accept all values. But omit -L/-I for /usr.
For libpcap default search use AC_CHECK_LIB, AC_CHECK_HEADER. For
manual libpcap spec, accept all values. But omit -L/-I for /usr.

dcrossleyau/yaz,nla/yaz,nla/yaz,dcrossleyau/yaz,nla/yaz,nla/yaz,dcrossleyau/yaz