* lex.l (update_yylval): Constify.
	* treelang.h (struct token_part, struct parameter_part):
	Likewise.
	* treetree.c (tree_code_create_function_prototype,
	tree_code_create_variable, tree_code_get_integer_value):
	Likewise.
	* treetree.h (tree_code_get_integer_value,
	tree_code_create_function_prototype, tree_code_create_variable):
	Likewise.

From-SVN: r126973