source code reorg & makefiles

I have one small request vis-a-vis the source code reorg.

Please don't undo the non-recursive make support. I put a lot of effort
into getting it where it was up to (even though that wasn't propogated
across the entire code base). It makes a substantial difference to
correctness, performance and ease of use of incremental builds.

Where the goal is to split out a Makefile, I suggest the use of an
include to incorporate smaller files.

I can see a number of regressions in this to-date, which is why I'm
asking that we not let it slide anymore.

-Rob