Improve configure.in so it can be used outside the Samba source tree.
Autobuild-User: Richard Sharpe <sharpe@samba.org>
Autobuild-Date: Thu Nov 17 07:00:38 CET 2011 on sn-devel-104
(cherry picked from commit
f50aa988c201c2fe78e467f1a419bedc741e1d31)
Fix bug #8607 (The configure.in in examples/VFS does not easily allow building
modules outside the Samba source tree).
(cherry picked from commit
7db7ea684a17b70ecae31c70c1b2e647ea0fafa1)
(cherry picked from commit
0a6d7a9ff9c96771ac0d5ca8159c5a2246cae782)