That isn't all that hard to do, CMake routinely supports this for e.g. Swig or Qt's moc/uic/rcc tools. The code generator creates a bunch of files and those can

That isn't all that hard to do, CMake routinely supports this for e.g. Swig or Qt's moc/uic/rcc tools. The code generator creates a bunch of files and those can be either built as a library or added to your normal list of sources.