Updating waf to 1.6

[Kevin Kofler]

Simo Sorce wrote:
> As far as I know the waf author himself considers embedding the right
> way to go for projetcs.

That shows that that upstream is completely wacky and it's idiotic for ANY 
project to rely on his code!

> Samba4 (and soon talloc, tdb tevent, we are building them these days)
> do embed their own copyof waf together with project extensions to waf.
> 
> The best thing is to not package waf on and in itself, and let package
> embed the right version. At least until waf becomes mature enough that
> the rate of change slows down to the point that option 1 becomes
> feasible.

The best thing is to get those projects to switch to a sane build system 
(http://www.cmake.org/) which cares about backwards compatibility and 
doesn't bundle itself nor any generated shell scripts.

Failing that, they need to be patched to build with the version of waf we 
ship, whether it's newer or older than the one upstream uses.

        Kevin Kofler