Memory fixes to JSON export.

core/c/mpw-util.h

@@ -122,6 +122,9 @@ const char *mpw_hex_l(uint32_t number);
 /** Encode a fingerprint for a buffer.
   * @return A C-string in a reused buffer, do not free or store it. */
 const char *mpw_id_buf(const void *buf, size_t length);
+/** Compare two fingerprints for equality.
+  * @return true if the buffers represent identical fingerprints. */
+bool mpw_id_buf_equals(const char *id1, const char *id2);
 /** Encode a visual fingerprint for a user.
   * @return A newly allocated string. */
 const char *mpw_identicon(const char *fullName, const char *masterPassword);