(char-db-ignored-attributes): New variable.

(char-db-ignored-attributes): New variable.
(char-db-coded-charset-priority-list): Modify for new definitions of
big5 variants.
(char-db-insert-char-spec): Refer `char-db-ignored-attributes'; add
`ideographic-structure' into requesting non-CCS attributes if
requesting is nil.
(insert-char-attributes): Refer `char-db-ignored-attributes'.