lang/mono2 fails on NetBSD 6 i386, apparently due to bugs in boehm-gc,
where it doesn't use pthread calls correctly to find the stack:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=46147
and discussion about workarounds in mono by turning off boehm-gc:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=45828
It would be nice if someone were to fix boehm-gc or knows enough to
report it upstream. Upstream's HOMEPAGE did not immediately indicate a
bug tracker, but the source is now on github and seems active.