* add.c (add), checkout.c (checkout_proc), client.c

(call_in_directory), find_names.c (Find_Names, Find_Directories),
recurse.c (start_recursion), update.c (update_dir_leave_proc,
isemptydir): Pass update dir to Entries_Open(), Find_Names(),
Find_Directories(), & isemptydir().  Do not call
Entries_Close().
* import.c (process_import_file): Ditto.  Use new internal prototypes.
(import_descend, import_descend_dir): Maintain and/or pass through new
update dir argument.
(import): Pass starter update dir argument to recursive
import_descend().
* entries.c: Include new headers.
(Entries_Close): Declare static.
(struct entries_cache_s): New struct.
(entries_cache_delproc, Entries_Close_Cache): New functions.
(Entries_Open): Use cache.
* update.h (isemptydir): Update prototype.
* cvs.h (Entries_Open, Find_Directories, Find_Names): Update protos.
(Entries_Close): Remove proto.