Дмитрий Архипов via Boost
The long answer follows.
Thanks, interesting.
As b2 is not a package manager, it doesn't have a special understanding of build and target platforms.
Hm, I don't see why this understanding can only be achieved in the package manager. It is true that the specification of dependencies between packages is where traditionally the built- time vs run-time distinction is made. But this knowledge is only necessary to automatically sort the packages into correct configurations. Provided that things are manually configured to build for host/target, nothing should prevent a build system from handling the rest. At least that's how it works in build2 (where the package manager sits on top of the build system rather than them being fused together).