'Set up the environment of packages that depend on this one.
This is similar to ``setup_environment``, but it is used to
modify the compile and runtime environments of packages that
*depend* on this one. This gives packages like Python and
others that follow the extension model a way to implement
common environment or compile-time settings for dependencies.
This is useful if there are some common steps to installing
all extensions for a certain package.
Example:
1. Installing python modules generally requires ``PYTHONPATH`` to point
to the ``lib/pythonX.Y/site-packages`` directory in the module\'s
install prefix. This method could be used to set that variable.
Args:
spack_env (EnvironmentModifications): List of environment
modifications to be applied when the dependent package is
built within Spack.
run_env (EnvironmentModifications): List of environment
modifications to be applied when the dependent package is
run outside of Spack. These are added to the resulting
module file.
dependent_spec (Spec): The spec of the dependent package
about to be built. This allows the extendee (self) to query
the dependent\'s state. Note that *this* package\'s spec is
available as ``self.spec``.'

def setup_dependent_environment(self, spack_env, run_env, dependent_spec):

    pass
