[Iftop-users] iftop build fials: POSIX threads in NetBSD

I'm trying to build iftop on my NetBSD-1.6.1 machine, but the config script dies with a complaint about POSIX threads:

[...]

checking pcap.h usability... yes checking pcap.h presence... yes checking for pcap.h... yes checkingfor a curses library containing mvchgat... -lncurses checking how to compile a working program with POSIX threads... no idea configure: error: can't figure out how to compile with POSIX threads If your system actually supports POSIX threads, this means we've messed up.

Has anyone else tried building iftop for NetBSD or have any experience with POSIX threads in NetBSD?