Since Boost tends to be difficult to work with, please note the
following changes in the near future:

 - dev-libs/boost-1.52.0-r6 is likely going to get stable due to a
security issue[1]; most of ~arch is already fixed to work with it, but
some more packages might require new stable versions, the tinderbox will
help there;

 - as soon as the stabilization procedure starts, dev-libs/boost-1.53.0
will be unmasked (given that tools can be built [2]), even though we do
have some latent bugs to be fixed[3] — as it seems like it's the only
way to get people to actually fix their bugs.

Both these versions support subslots, so if you want to start adding
dependencies to them, you've got the greenlight now.

You might also want to make sure that, if you need the multithreaded
variant, you depend on [threads(+)] with USE-dependencies.

Thank you all!

[1] https://bugs.gentoo.org/show_bug.cgi?id=455464
[2] https://bugs.gentoo.org/show_bug.cgi?id=459112
[2] https://bugs.gentoo.org/show_bug.cgi?id=boost-1.53.0

-- 
Diego Elio Pettenò — Flameeyes
flameeyes@flameeyes.eu — http://blog.flameeyes.eu/