boost.build unique feature

With boost.build it is possible to integrate different projects with each other. For instance, when you have a project which uses the Boost libraries you can merge both projects by stating

use-project boost : /path/to/boost/sources ;

in a Jamfile of your project.
All build targets of the boost project are then accessible just like any other target. They are build on demand with the same build options and are cleaned by clean-all. You can simply refer to them like this:

exe foo : foo.cc : <library>/boost//program_options ;

To make it clear: boost has not to be build or installed in advance. You simply refer to the boost.build project and your build system takes care of anything else. I am not aware of any other build system which provides this feature.

Update: The above is the generic scheme for integration with other Boost.Build projects. If you want to use the boost library you can integrate it like this:

import boost ; boost.use-project ;