combined s3/s4 build - initial build working

[tridge at samba.org]

Hi Metze,

 > I've just build the current version of your toplevel-wip branch,
 > it's nice that the s3build/ directory isn't needed anymore.

yep, its now unified with the source3/ waf build

 > Currently smbd links against libgensec.so.0, libldb.so.1,
 > libsamba-util.so.0, libsamba-sockets.so, libcredentials.so,
 > libsamdb.so.0 and a few others, which should not be needed.

yep, and there are also problems with debug calls.

I think the two are related. We need to use the wafsamba symbol
validation tests to find all the places where we end up with duplicate
symbols.

 > Please let me review the final branch before you push to master.

I don't want to wait for this to be perfect before we push it to
master. It is disabled by default, and it doesn't impact on the
current toplevel s4 build, or the source3/ waf build or the s3
autoconf build. 

I'd like to get it into master soon so it doesn't diverge from the
work Günther has been doing on the source3/ waf build.

Cheers, Tridge