The <define> property in Boost.Build does not propagate. This causes problems in my project, as the unit tests require a macro UNIT_TEST to be defined and the main library is built with this macro defined. Because <define> does not propagate, I have to specify <define>UNIT_TEST at the command line. If the library is built first without this macro, the unit tests will not be built successfully.

I am considering to add a <unit-test> feature and make <define>UNIT_TEST propagate.

Import feature : feature ;

Feature unit-test : on off : propagated ;

But how to add <define>UNIT_TEST when <unit-test>on?

Thanks.