Peter Dimov via Boost
Since the CMake configuration files that are generated by `b2 install` define CMake targets based on the b2 targets, it's not possible to fix this just on the boost-install side. If we want Boost::process to appear as a target in CMake, we need boost_process to appear as a target in b2, that is, we need libs/process/build/Jamfile to exist.
The easiest way to fix it - if we decide to do something about it - is to create dummy compiled libraries for each such header-only library that isn't really header-only because of dependencies.
Wouldn't the proper way to fix this be to teach b2 first-class "binless" library targets (i.e., a library that doesn't actually have .a/.so)? This will also allow you to, say, have "binful" .so (for example, due to DllMain) but "binless" .a, if you ever want such a beast (no pun intended).