Re: Small improvements to pg_list.h's linitial(), lsecond(), lthird() etc macros

Poking around to count remaining uses of those inline functions,
I found a few places that should be using the macros instead,
and fixed them.  After that, I notice that list_tail(),
list_third_cell(), and list_fourth_cell() are entirely unreferenced.
I'm hesitant to get rid of list_tail(), because it seems like it
could well be used by extensions.  But I'd bet quite a bit that
list_third_cell() and list_fourth_cell() are not used anywhere
anymore.  Should we get rid of them to shave a few microseconds
from compile times?

			regards, tom lane