make install in the brave new build system world

[Christoph Hellwig]

On Fri, Feb 05, 2010 at 09:44:14PM +1100, Dave Chinner wrote:
> The dependencies are always regenerated due to the default target
> requiring the depend target. Rebuilding the dependencies is the only
> way to catch changes between builds and so ensure the correct files
> are rebuilt.
> 
> The install target is building the dependencies because it has a
> dependency on the default target.

Well, it's building the dependecies twice - once by invoking the
default target, but they are also rebuilt again when the actuall
install rules are called.   The latter is pretty clearly superflous.