dprintf level fmt args... formats the logging information fmt
with the arguments args... on the logging output if the logging
level is greater than or equal to level.
fold f entry x iterates f over the entries and an accumulator
initially containing x; at each iteration, f gets the current
value of the accumulator and returns its new value.
non_dependency module_path module_name
Example:
non_dependency "foo/bar/baz" "Goo"
Says that the module Baz in the file foo/bar/baz.* does not depend on Goo.