Hi,
I am currently working on an iftop package for OpenCSW for Solaris 9 Sparc and noted that neither 0.17 not 1.0pre2 work with libpcap 1.1.1 - they just show zeros for the stats and no connections. They do work with older versions of libpcap like 0.9.4.
Additionally, I needed a couple of patches to compile it on Solaris 9 with GCC 3.4.6 which you may want to incorporate: http://sourceforge.net/apps/trac/gar/browser/csw/mgar/pkg/iftop/trunk/files
Edit: My patches are essentially the same as the ones posted here: http://lists.beasts.org/pipermail/iftop-users/2011-October/000354.html
Best regards
-- Dago