On 1.8.x-apr-0.9 branch, support for 0.9.x including 0.9.20.

* configure.ac
  (APR_VER_REGEXES): Allow 0.9.2?.
 
* subversion/include/private/svn_dep_compat.h
  (apr_hash_make_custom): Provide.

* subversion/tests/libsvn_wc/utils.c
  Include svn_dep_compat.h.

* subversion/libsvn_subr/prompt.c
  (terminal_open): Use compatibility names.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.8.x-apr-0.9@1585499 13f79535-47bb-0310-9956-ffa450edef68