The following reply was made to PR toolchain/30097; it has been noted by GNATS.

From: dholland@eecs.harvard.edu (David Holland)
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: toolchain/30097: CFLAGS+=-W when ${WARNS} > 3
Date: Fri, 13 Oct 2006 02:11:17 -0400 (EDT)

  > # in <bsd.sys.mk>:
  > .if ${WARNS} > 3
  > CFLAGS+=	-W
  > .endif
 
 I tried this, and it doesn't work very well, at least for now.
 
 The first thing you find is that there's a lot of code in libc that is
 marked /*ARGSUSED*/ for lint but doesn't have __unused markings for
 gcc. Patching all this in is lengthy and gets kind of ugly in places,
 and after going through all of citrus I gave up.
 
 So you'd need at least -W -Wno-unused.
 
 This still breaks in a lot of places with warnings about missing
 initializers; gcc doesn't like it when you do
 
 	struct foo foo_array[] = {
 		{ 1, 2, 3 },
 		{ 4, 5, 6 },
 		     :
 		{ 0 },
 	};
 
 because it really wants you to have an initializer for every field.
 This behavior is, IMO, lame, so one turns out to want -W -Wno-unused
 -Wno-missing-field-initializers.
 
 I haven't gotten any further than this yet, but I thought I'd report
 this much as it may be a while before I try again.
 
 Oh, and according to the gcc4 manpage "-Wextra" is now the preferred
 name for -W. FWIW.
 
 -- 
    - David A. Holland / dholland@eecs.harvard.edu