At configuration time, before building, users can select
the ntpserver to be used to prime WR time at boot.  By default
no server is queried.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Developers may want to preserve the filesystem image, to verify the
effect of configuration options, avoiding the need to untar
images/wrs-image.tar.gz every time.

I personally used it to verify the next commits, other people may
prefer to keep it disabled.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The PPSi daemon can now be selected in Kconfig. This commit
changes configuration and the build scripts to support either of them.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Both the buildroot and busybox config files are not hosted in
configs/buildroot/ within wr-switch-sw, where I expect to place
several such configuration files, at least to try different setups.

The name of the buildroot configuration file is not chosen using
Kconfig (but the default is silently applied.  If the user
provides a relative pathname, it is expanded to
wr-switch-sw/configs/buildroot .

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The Makefile was empty, this only adds the kconfig rules
and a default target that make silentoldconfig

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>