def getRoot(config):
    if not config.parent:
        return config
    return getRoot(config.parent)


root = getRoot(config)

# Only run if we have an instrumented libcxx.  On Darwin, run always (we have
# interceptors to support the system-provided libcxx).
if not root.has_libcxx and root.host_os != "Darwin":
    config.unsupported = True
