On the 'move-tracking-2' branch: Don't warn about functions returning an
aggregate (structure) value, as it's convenient to do so on this branch.

* configure.ac
  (CMAINTAINERFLAGS): Remove '-Waggregate-return'.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1627249 13f79535-47bb-0310-9956-ffa450edef68