Comment # 5 on bug 1168828 from Michal Kube��ek

In general, reported config options are those for which "make oldconfig"
would prompt you for a value. Technically, the build could use e.g. the
default (what is used if you just press enter) but we find it potentially
dangerous and the check is in place to make sure provided config is complete
and doesn't  leave any config values undetermined.

What you should keep in mind is that

  (1) changing the value of one option can make other options visible so that
      you need to provide their values
  (2) changing an option which is part of a "radio button" set usually results
      in change of other related options