Set variable indicating indicating full build

Some of the modules should work as standalone projects and may
therefore be able to determine between a full build or a module
build.

Change-Id: I25ea2b7afcaa45305ca72346b1d5bd9f4b552ced
Reviewed-on: http://review.couchbase.org/42885
Reviewed-by: Dave Rigby <daver@couchbase.com>
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>