Re: misc/54581: Issues building NetBSD-9 under NetBSD-5.2

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sat, 28 Sep 2019 09:07:43 -0700
    From:        Brian Buhrow <buhrow%nfbcal.org@localhost>
    Message-ID:  <201909281607.x8SG7iuU018476%lothlorien.nfbcal.org@localhost>

  | 1.  I tried using the definitions from sys/cdefs.h in netbsd-90 sources,
  | but gcc 3.3.x didn't like the final usage when I tried to compile
  | everything up.

I didn't want to throw cold water on your efforts earlier, but you're
likely to suffer from more than that ... I gave up trying to build HEAD
on a -6 based system a while ago (before -9 branched I believe) as
the gcc that it contains wasn't up to the task of even building the
tools any more (or that's what I remember ... it has been a while now).

That is, I am not sure you will ever really get a satisfactory -9 or HEAD
build on a -5 system - which is a real pity, the cross build environment
should work anywhere (building anything that is needed where an old or
other system's version is not adequate).

  | Thoughts?

But for __CTASSERT() it really doesn't matter what you define it to be,
just as long as it doesn't break compilation.    Actually though, for
-9 the fixes needed to use the new form from HEAD may not have been pulled
up (there were a few bad __CTASSERT uses that needed fixing.)   So using
the form from HEAD might not be the right thing to do after all.

It is after all just a compile time assert - its purpose is to make sure
that no-one accidentally changes the sources in a way that voilates
assumptions made elsewhere in the code.   All that is needed for that to
be effective is for someone to compile with a working version of the macro.
That someone can be anyone - including the buildbots.   So simply defining
the macro to ignore its args and generate nothing at all should not hurt
your build at all.

kre