Review Request: Build-infra M1

[Michael McMahon]

A few more things I'd like to understand are:

1) In what circumstances exactly would the configure script have to be 
re-run?

2) Can you give examples of the kind of build changes that would be 
needed :-
      - when a small'ish change is made (eg adding a couple of new 
source files, or renaming
         or removing them)?
     -  when a new component is added, with both Java and native sources 
in new source directories

Thanks,
Michael