On the fsx branch:  Merge the patches pertaining to the new
svn__prefix_string_* private API (rr1498029) from /branches/fsfs-format7.
There were no conflicts.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1507857 13f79535-47bb-0310-9956-ffa450edef68