* c-exp.y (%union) <type_stack>: New field.

	* c-exp.y (%union) <type_stack>: New field.
	(abs_decl, direct_abs_decl): Use <type_stack> type.  Update.
	(ptr_operator_ts): New production.
	(ptype): Update.
	* parse.c (type_stack_reserve): New function.
	(check_type_stack_depth): Use it.
	(pop_type_stack, append_type_stack, push_type_stack)
	(get_type_stack, type_stack_cleanup): New functions.
	(follow_types): Handle tp_type_stack.
	(_initialize_parse): Simplify initialization.
	* parser-defs.h (enum type_pieces) <tp_type_stack>: New
	constant.
	(union type_stack_elt) <stack_val>: New field.
	(get_type_stack, append_type_stack, push_type_stack)
	(type_stack_cleanup): Declare.
testsuite
	* gdb.base/whatis.exp: Add tests.