oidin / oidout and InvalidOid

Hi,

I was recently guilty of writing a less-than-clear SQL example
because I plain forgot whether InvalidOid was 0 (correct) or -1
(my bad).

Would there be any sense in letting oidin_subr accept the string
InvalidOid for 0? I understand that changing oidout could break
existing code outside of the tree. But what if oidout were to be
conservative in what it does, and oidin liberal in what it accepts?

-Chap