Cannot build from system headers

[jefftrull]

Based on speaking with Michael, it is supposed to be possible to build using system headers/libs if BOOST_ROOT is not supplied. This does not appear to work on my system (Ubuntu 14.04).

[jefftrull]

I should clarify that this is an issue with running bjam.

[burlog]

Yes, on Gentoo does not work too but cmake works fine :).