On the fsx branch:  Copy the FSX code over from the fsfs-format7 branch
and update the glue code as well as the build scripts to enable it.

* subversion/libsvn_fs_x
  (): copy the whole sub-tree from /branches/fsfs-format7@HEAD

* subversion/libsvn_fs_x/tree.c
  (root_vtable): disable the "dir_optimal_order" vtable entry for now
                 because this extension still sits in fsfs-improvements
                 waiting to be reviewed and merged into /trunk

* subversion/include/svn_error_codes.h
  (SVN_ERR_FS_MALFORMED_TXN_ID,
   SVN_ERR_FS_ITEM_INDEX_CORRUPTION,
   SVN_ERR_FS_ITEM_INDEX_REVISION,
   SVN_ERR_FS_ITEM_INDEX_OVERFLOW,
   SVN_ERR_FS_CONTAINER_INDEX,
   SVN_ERR_FS_ITEM_INDEX_INCONSISTENT): declare new error codes

* subversion/include/svn_fs.h
  (SVN_FS_TYPE_FSX): declare new FS type
  (SVN_FS_CONFIG_COMPATIBLE_VERSION): new config variable
  (svn_fs_create): mention the new FS in the docstring
  (svn_fs_fsx_info_t): declare new FS info type

* subversion/libsvn_fs/fs-loader.h
  (svn_fs_x__init): declare new FS init function

* subversion/libsvn_fs/fs-loader.c
  (fsx_defn): register new FS type
  (fsfs_defn): chain the FS definition

* subversion/svnadmin/svnadmin.c
  (cmd_table): 'pack' now makes good use of the "-M" parameter
  (subcommand_create): set SVN_FS_CONFIG_COMPATIBLE_VERSION config variable;
                       disable FSX for pre-1.9 compatibility

* build.conf
  (private-built-includes): filter FSX's rep-cache-db.h as well
  (libsvn_fs_x): declare new target
  (rep_cache): rename target to ...
  (rep_cache_fs_fs): ... this one
  (rep_cache_fs_x): new target
  (fs-libs): add dependency to FSX

* configure.ac
  (SVN_LIBSVN_FS_LINKS_FS_X): new config variable

* subversion/svn_private_config.hw
  (SVN_LIBSVN_FS_LINKS_FS_X): new config variable


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508041 13f79535-47bb-0310-9956-ffa450edef68