[ecj] gjar is installed, but we don't use it in the build

[Andrew Haley]

Tom Tromey writes:
 > Andrew> I've been having a lot of trouble with broken build dependencies.  If
 > Andrew> you, say, delete a fle in the build tree, make doesn't know how to
 > Andrew> rebuild it.  You have to delete the build tree and start again.
 > 
 > What sorts of files trigger this?

I'll start making notes.

Andrew.