Samba 4 build system - more thoughts on scons

[tridge at samba.org]

 > Last time I looked at the configure replacement stuff it didn't look
 > terribly useful.  It might be easier to switch one bit at a time - first
 > the build system, dependencies etc, then the configure business.

the problem is that the two are linked. configure results are used to
decide what object files to build and what libraries to link. The
interface between these two is where things get particularly messy.