Improved build system

[Fredrik Öhrström]

2011/9/30 Jonathan Gibbons <jonathan.gibbons at oracle.com>:
> How well will this extend, in time, to support more fine-grained
> dependencies, at (say) the top-level-class level?

For the makefiles, it really does not make sense to do more fine-grained
dependency tracking than packages, since the minimal recompilation
is a full package. Imho triggering recompilations of other packages
based on the pubapi of the full package, not just the classes, is beneficial
since it causes the programmer to think about how the packages are
structured and import each other. Even though it causes unnecessary
recompilations.

But as I wrote in the file JavaCompilation.gmk, it would make sense
to move the code in JavaCompilation.gmk into a smarter javac.
This smarter javac could possibly track dependencies on a more
fine-grained basis.

There is an option named groupon=package that can be set to groupon=class
and passed to deps,pubapi,nativeapi above. It probably does not work,
since I have not tested it for a along time.

//Fredrik