Enable chained function calls in C++ expressions.

Enable chained function calls in C++ expressions.

gdb/ChangeLog:

	* eval.c: Include gdbthread.h.
	(evaluate_subexp): Enable thread stack temporaries before
	evaluating a complete expression and clean them up after the
	evaluation is complete.
	* gdbthread.h: Include common/vec.h.
	(value_ptr): New typedef.
	(VEC (value_ptr)): New vector type.
	(value_vec): New typedef.
	(struct thread_info): Add new fields stack_temporaries_enabled
	and stack_temporaries.
	(enable_thread_stack_temporaries)
	(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
	(get_last_thread_stack_temporary)
	(value_in_thread_stack_temporaries): Declare.
	* gdbtypes.c (class_or_union_p): New function.
	* gdbtypes.h (class_or_union_p): Declare.
	* infcall.c (call_function_by_hand): Store return values of class
	type as	temporaries on stack.
	* thread.c (enable_thread_stack_temporaries): New function.
	(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
	(get_last_thread_stack_temporary): Likewise.
	(value_in_thread_stack_temporaries): Likewise.
	* value.c (value_force_lval): New function.
	* value.h (value_force_lval): Declare.

gdb/testsuite/ChangeLog:

	* gdb.cp/chained-calls.cc: New file.
	* gdb.cp/chained-calls.exp: New file.
	* gdb.cp/smartp.exp: Remove KFAIL for "p c2->inta".