Can't express "construct derived type using procedure for base type, but with these changes"

[Dave Abrahams]

For example, we have PYTHON_EXTENSION derived from SHARED_LIB. The generator for PYTHON_EXTENSION just needs to add _d to the name in some cases. When it calls the SHARED_LIB generator it produces targets of type SHARED_LIB, not PYTHON_EXTENSION, and we have no easy way to fix that up.

[Dave Abrahams]

Maybe the easiest way to implement this is to pass the desired target type in as a property. You'd just need to make sure that the property gets filtered out when dependencies are generated.