bin/52355: address-of-packed member causes clang build of NetBSD/amd64 -7 to fail

[jan.m.danielsson%gmail.com@localhost]

>Number:         52355
>Category:       bin
>Synopsis:       address-of-packed member causes clang build of NetBSD/amd64 -7 to fail
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 01 23:55:00 +0000 2017
>Originator:     Jan Danielsson
>Release:        netbsd-7
>Organization:
La Cosa Nostra
>Environment:
NetBSD gauss.local 7.0_STABLE NetBSD 7.0_STABLE (GAUSS) #0: Sun Oct 23 03:20:17 CEST 2016  jan@gauss:/home/jan/tmp/sysbuild/obj.amd64/usr/src/sys/arch/amd64/compile/GAUSS amd64
>Description:
A while into the build the following error causes the build to abort:

error: unknown warning option '-Werror=address-of-packed-member' [-Werror,-Wunknown-warning-option]

external/bsd/tcpdump/bin/Makefile unconditionally sets:

CWARNFLAGS.clang+=	-Wno-error=address-of-packed-member

>How-To-Repeat:
Build native build of netbsd/amd64 -7 using:

MKLLVM=yes
HAVE_LLVM=yes
MKGCC=no
>Fix:
Not sure what the proper solution is, but naively commenting out CWARNFLAGS.clang in external/bsd/tcpdump/bin/Makefile gets the build to pass.