Merge the latest build script from ARM's internal repository.

Taken at this SHA ID:
  035649e618f1471413e220ec558a8360b4769d71

  035649e  2016-05-27  build-script refactor      [Sudipto Paul]

This patch squashes down the change history from the series on the
internal tree to this single revision.

Change-Id: I70352fd520aa5206379bb417c6d7e93935b9f101
Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org>