Error while building synfig/synfig.git master branch for OSx

Development Building synfig
1
  1. I checked out github.com/synfig/synfig using the master branch
  2. Installed Xcode developer tools, git, svn, homebrew, etc.
  3. I cd into synfig/autobuild
  4. I run sudo ./synfigstudio-osx-build.sh

It displays a lot of stuff but then at the end I get this:

./rendering/resource.h:103:9: error: binding value of type ‘const vector<[…]>’ to reference to type ‘vector<[…]>’ drops ‘const’ qualifier
List &resources = get_alternatives();
^ ~~~~~~~~~~~~~~~~~~

I haven’t made any changes to the code. Any reason for this?