'Compute the dependencies of a gyp spec.
Returns a tuple (deps, link_deps), where each is a list of
filenames that will need to be put in front of make for either
building (deps) or linking (link_deps).'

def ComputeDeps(self, spec):

    deps = []
    link_deps = []
    if ('dependencies' in spec):
        deps.extend([target_outputs[dep] for dep in spec['dependencies'] if target_outputs[dep]])
        for dep in spec['dependencies']:
            if (dep in target_link_deps):
                link_deps.append(target_link_deps[dep])
        deps.extend(link_deps)
    return (gyp.common.uniquer(deps), gyp.common.uniquer(link_deps))
