Strawman: fix for javac task in ant

[KB Sriram <kb...@skytalk.com>]

Following up on the problem with the javac task in ant not identifying
the correct set of files to be recompiled, thought I'd write a strawman
on some possible strategies to fix it.

1. Not fix it at all :-) To make sure everything is still working,
   periodically run a clean + build.
2. Use separate dependency file that can be automatically (re)generated
   if necessary.
   2.1 Have the compiler itself regenerate this dependency file at the
   end of compilation (cons: non-standardized format, compiler may not
   be able to do this. pros: most efficient)
   2.2 Have a separate library that runs after compilation (say something
   like javadepend http://www.cs.mcgill.ca/~stever/software/JavaDeps/)
   to regenerate the dependency file.
      2.2.1 Automatically run the tool on changed source files after a
successful
      compile (i.e. making it part of the javac task itself.)
      2.2.2 Have an explicit task that runs the tool (aka "make depend") on
demand.
   (pro for 2.2: need not depend on compiler's ability to generate
dependency file,
   can standardize format. con for 2.2: more complex system, need to track
JLS,
   less efficient.)

Comments?
-kb-