[LinuxBIOS] make dependencies and C includes

[Robert Millan]

Hi!

I've observed that C #include'd files such as raminit.c aren't represented
in make dependencies, resulting in them not being recompiled after a
modification.

I'm not sure what would be the proper solution:

- add the dependency manually in the corresponding Config.lb files?
  - migrate use of #include to separate compilation and standard linking?
  - modify util/newconfig/config.g to automatical scan C files and add
    the dependencies for #includes?