Log Message:
Update to 1.8.12:

NEW IN WAF 1.8.12
-----------------
* Fixed a regression when building in sub-folders - \ 
https://github.com/waf-project/waf/issues/1590
* New mac_files attribute which is expected to replace mac_resources in waf 1.9 \ 
(demos/mac_app/)
* env = env.derive().detach() to simplify deep copies