On the fsx branch: follow-up to r1508120.
Rename svn__prefix_tree_* to svn_prefix_tree__*.

* subversion/include/private/svn_string_private.h
  (svn__prefix_tree_*): rename to ...
  (svn_prefix_tree__*): ... this

* subversion/libsvn_subr/prefix_string.c
  (svn__prefix_tree_*): rename to ...
  (svn_prefix_tree__*): ... this
  (auto_realloc_sub_nodes,
   svn_prefix_string__create): update type references

* subversion/libsvn_fs_x/pack.c
  (pack_context_t,
   initialize_pack_context): update API users

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508439 13f79535-47bb-0310-9956-ffa450edef68
On the fsx branch: add a test for the svn_prefix_string_* API.

* build.conf
  (prefix-string-test): declare new target
  (__ALL_TESTS__): register new target

* subversion/tests/libsvn_subr/prefix-string-test.c
  (): new file

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508441 13f79535-47bb-0310-9956-ffa450edef68
On the fsx branch: Fix a bug in svn_prefix_string__expand detected
by the new test code.

* subversion/libsvn_subr/prefix_string.c
  (svn_prefix_string__expand): actually copy data into the target buffer

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508444 13f79535-47bb-0310-9956-ffa450edef68
On the fsx branch:  Remove a few unused variables from the test code.

* subversion/tests/libsvn_subr/prefix-string-test.c
  (a, b, c, phrase_1, phrase_2): drop

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508446 13f79535-47bb-0310-9956-ffa450edef68