Re: Header / Trailer Comment Typos for M4 macros

Jesse Zhang <sbjesse@gmail.com> writes:
> I didn't make my question clear though: I'm curious what motivated the
> original addition of -Wno-unused-command-line-argument in commit
> 73b416b2e412, and how that problem did't quite manifest itself with Clang++.

We didn't then have the convention of mentioning relevant mailing list
threads in the commit log, but some excavation finds

https://www.postgresql.org/message-id/flat/CALkS6B8Ei3yffHTnUsAovCPmO9kPTpgCArwyod7Ju2eWBm6%3DBA%40mail.gmail.com

So it seems to have been specific to clang circa version 6.0.  Maybe
the clang boys thought better of this behavior more recently?

[ experiments... ]  I see no warnings on current macOS (Apple clang
version 11.0.3) after removing the switch.  So I guess they did fix it.

We're pretty conservative about dropping support for old toolchains,
though, so I doubt that we'd want to remove this configure check.
Especially if we don't know how long ago clang changed it.

            regards, tom lane