* tree.h (get_identifier) Define a macro form of get_identifier

* tree.h (get_identifier) Define a macro form of get_identifier
	that calls get_identifier_with_length when the string is constant.
	(get_identifier_with_length): Change type of second argument to
	size_t in prototype.
	* stringpool.c (get_identifier): Undefine the macro before giving
	the function definition.
	(get_identifier_with_length): Change  type of second argument to
	size_t in function definition.
	* hashtable.c (calc_hash): Change type of second argument to size_t.
  	(ht_lookup): Change type of third argument to size_t.  Reorganize
	to speed-up the cases where the hash table slot is empty, or the
	first probe matches (i.e. there isn't a collision).
	* hashtable.h (ht_lookup): Adjust function prototype.

From-SVN: r70256