build process doesn't work as expected

When running the proposed command line sequence:

$ python bootstrap-buildout.py
$ ./bin/buildout

the compilation starts at the bob.io.image package (the first entry in layer1.cfg, not (as I would have expected) from bob.buildout in layer0.cfg. I don't understand the reason for that, but the fix is simple: In layer0.cfg, replace:

develop += ...
eggs += ...

with:

develop = ...
eggs = ...

I think, there was a debug.cfg, from which layer0.cfg was inheriting, but this is no longer true (and the file is no longer available). There might be better fixes, but this solved it for me.