As before, I should note that I initially wrote this post on a machine with Boost
in a standard system location. So stuff just works. Others may have had to install Boost from source,
and into a non-standard location, which may have required an -I flag,
not unlike how we initially added
the C++11 flag in this post before the corresponding plugin was added.
This is now automated thanks to the
BH package which, if installed, provides Boost headers
for use by R in compilations just like this one.