as suggest on page 6 of:
http://www.boost.org/doc/tools/build/doc/userman.pdf
into the 'body' of exe 'options' in the Jamroot file inside my project. I had previously tried to add it just at the end that file.

My problem was that I was provided with a working Jamroot file (by somebody who has since left my organisation) and thus I was able to work happily without knowing anything about the syntax in it. I was foraging through the boost documentation how to get started with it and only found that little bone:
" you need a directory containing the boost/ subdirectory in your #include path. "
in: http://www.boost.org/doc/libs/1_39_0/more/getting_started/unix-variants.html
but no documentation of how to actually add a include path (because that is probably obvious to anybody familiar with bjam).

And, I am wondering whether I should rather add that line to my /usr/share/boost-build/user-config.jam file but the syntax probably is slightly different there.

Markus