File boost-default_extension.patch of Package boost

See https://svn.boost.org/trac/boost/ticket/2224

The default extension is wrong for string_type==std::wstring and causes a
compiler error.


--- boost/filesystem/path.hpp
+++ boost/filesystem/path.hpp
@@ -203,7 +203,7 @@
       }
 
       basic_path & remove_filename();
-      basic_path & replace_extension( const string_type & new_extension = "" );
+      basic_path & replace_extension( const string_type & new_extension = string_type() );
 
 # ifndef BOOST_FILESYSTEM_NO_DEPRECATED
       basic_path & remove_leaf() { return remove_filename(); }