Let NetBSD/clang package.
Final ling gets 'unresolved reference', also found on FreeBSD/ports.
  http://lists.freebsd.org/pipermail/freebsd-ports-bugs/2012-December/245884.html
Checked on
  NetBSD/amd64 6.99.16
  clang version 3.2 (trunk 168187)
  Target: x86_64--netbsd
And also
  NetBSD/amd64 6.0.1
  gcc (NetBSD nb2 20110806) 4.5.3
Thanks wiz for the information.