kbx: Fix keyboxd searching with multiple patterns.

* kbx/keybox-search-desc.h (struct keydb_search_desc): New flag
name_used.
* common/userids.c (classify_user_id): Set flag.
* kbx/kbxserver.c (struct search_backing_store_s): New.
(cmd_search): use a backing store for the const pointers.
(kbxd_start_command_handler): Release the backing store.
--

Well, the search object partly uses buffers but also const
pointers (for strings and the serial number).  This when assigning
such objects to an another one we should really take a deep copy and
not just copy the pointer.  The more clean solution would have been to
provide a storage option the search object but that needs checking the
code at too many places so that I decided to use a separate backing
store array here.

Signed-off-by: Werner Koch <wk@gnupg.org>

kbx/keybox-search-desc.h

@@ -83,6 +83,7 @@ struct keydb_search_desc
     unsigned char grip[KEYGRIP_LEN];
     unsigned char ubid[UBID_LEN];
   } u;
+  byte name_used;/* The union uses NAME.  */
   byte snhex;   /* SN above is a hexstring and not binary.  */
   byte fprlen;  /* Only used with KEYDB_SEARCH_MODE_FPR.  */
   int exact;    /* Use exactly this key ('!' suffix in gpg).  */