Penn will compile and run out of the box on NetBSD, including OpenSSL
support, with the caveats below.

* Mysql and Postgres should be detected if their packages have been
  installed through pkgsrc or pkg_add and /usr/pkg/bin is in your
  path. If you have the sqlite3 package installed and want to use it,
  you need to tell configure to look in the /usr/pkg hierarchy for it:

  % CPPFLAGS=-I/usr/pkg/include LDFLAGS=-L/usr/pkg/lib ./configure

* If you're using an IPv6-enabled install and 'sysctl
  net.inet6.ip6.v6only' prints out 1, you'll have to get a sysadmin to
  change it to 0 or run configure with --disable-ipv6 to allow IPv4
  connections.