Unbreak the build against recent Clang by backporting two patches from the
upstream (issue #1537368):

• Unconditional usage of std::auto_ptr<> in "vigra_ext" code: http://hg.code.sf.net/p/enblend/code/rev/467a73754dbb
• Get rid of `boost::assign::map_list_of' (additional patch): http://hg.code.sf.net/p/enblend/code/rev/73e6f16de80a

PR: 225557