Use libiberty hash in gas/macro.c.

Use libiberty hash in gas/macro.c.

	* config/tc-iq2000.c (iq2000_add_macro): Use htab hash table.
	* macro.c (struct hash_control): Use htab.
	(macro_init): Likewise.
	(do_formals): Likewise.
	(free_macro): Likewise.
	(define_macro): Likewise.
	(sub_actual): Likewise.
	(macro_expand_body): Likewise.
	(macro_expand): Likewise.
	(check_macro): Likewise.
	(delete_macro): Likewise.
	(expand_irp): Likewise.
	* macro.h (struct macro_hash_entry): New struct.
	(hash_macro_entry): New.
	(eq_macro_entry): Likewise.
	(macro_entry_alloc): Likewise.
	(macro_entry_find): Likewise.
	(struct formal_hash_entry): Likewise.
	(hash_formal_entry): Likewise.
	(eq_formal_entry): Likewise.
	(formal_entry_alloc): Likewise.
	(formal_entry_find): Likewise.