In Linux 4.18, various compiler version and feature tests are invoked
via kconfig rather than via kbuild. This means that we generally
cannot generate kconfig files for foreign architectures.
Move the config files to a new linux-config-<version> package which is
arch-dependent (and also M-A: same).
Make linux-config-<version> and linux-source-<version> recommend each
other.
Ben Hutchings