one recipe to be specified per target. When multiple recipes are defined for
the same target, only the last one will be executed.
This change makes executing the 'all' target in the controller/ or
controller/block/ directory actually only build files inside these directories
instead of starting a full build at the top level directory.
Making 'clean' in either of these directories still cleans the entire build
starting from the top level directory. I think this eventually deserves a
second commit. I would like to be able to only 'clean' a subdirectory.