Re: boost-libs patch

[coypu%sdf.org@localhost]

Yes, the new version of boost-libs did not build fiber on netbsd-8 and
the old did. too many platforms did not build it and now the ones that
do change, easier to just disable.

I saw your change, but I wasn't sure if it's safe to pullup. boost-libs
is a dependency to many things. Having it done by compiler version is
probably the way to go, but the first difference that showed up is that
apple clang can do it and mainline cannot (?)

Sorry about the breakage.