this makes modules with a binary helper simpler to build using the
parent module build harness as much as possible. i probably could
simplify this down to a single binary only and it is either setuid or
not... define the deps and flags ... it could be a bit simpler. not
much. i also removed the if's in the build for battery and ifdefs in
src handle it instead (imho simpler to maintain in src). sysinfo still
uses the if's there.