Follow-up to r1605123:

* subversion/include/svn_types.h
  (SVN_STR_TO_EOL): Point to the private alternative svn__strol() from
    a private (non-doxygen'd) docstring.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1605375 13f79535-47bb-0310-9956-ffa450edef68