port-vax/48042: after updating vax to new CSU stuff, various binaries get SIGSEGV on exit

[martin%NetBSD.org@localhost]

>Number:         48042
>Category:       port-vax
>Synopsis:       various binaries get SIGSEGV on exit
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-vax-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jul 10 10:40:00 +0000 2013
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.23
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD dead-to-the-world.duskware.de 6.99.23 NetBSD 6.99.23 (DEAD) #25: 
Tue Jul 9 06:02:37 CEST 2013 
martin%night-porter.duskware.de@localhost:/usr/src/sys/arch/vax/compile/DEAD vax
Architecture: vax
Machine: vax
>Description:

After recently upgrading my VAX to -current (as of a few days ago), several
(old and new) binaries started to segfault on program exit.

This includes important ones: sshd[1085]: fatal: privsep_preauth: preauth child 
terminated by signal 11

but is also reproducable with simpler to debug ones, like mini_sendmail
from pkgsrc (old, unchanged binary):

Starting program: /usr/pkg/sbin/mini_sendmail < /dev/null
/usr/pkg/sbin/mini_sendmail: could not open SMTP socket: Connection refused
Program received signal SIGSEGV, Segmentation fault.
0x7f6e8baf in __do_global_dtors_aux () from /usr/lib/libc.so.12
(gdb) bt
#0  0x7f6e8baf in __do_global_dtors_aux () from /usr/lib/libc.so.12
#1  0x7f787ce9 in _fini () from /usr/lib/libc.so.12
#2  0x7f7d684a in _rtld_call_fini_functions (2147469816, 1)
   from /usr/libexec/ld.elf_so
#3  0x7f7d6fc9 in _rtld_exit () from /usr/libexec/ld.elf_so
#4  0x7f77544b in __cxa_finalize (0) from /usr/lib/libc.so.12
#5  0x7f775318 in exit (1) from /usr/lib/libc.so.12
#6  0x00010ebf in ?? (74047)
#7  0x00011a09 in ?? (1, 2147478836, 2147478844)
#8  0x00010d26 in ??
    (1, 2147478836, 2147478844, 2138927022, 2138873856, 2147483632)
#9  0x00010c9b in ?? ()
(gdb) x/i 0x7f6e8baf
=> 0x7f6e8baf <__do_global_dtors_aux+67>:       calls $0x0,(r0)
(gdb) info reg
r0             0x0      0
r1             0x0      0


>How-To-Repeat:
s/a

>Fix:
Skipp NULL ctor/dtor pointers?