port-alpha/51678: gdb can't run threaded programs

[martin%NetBSD.org@localhost]

>Number:         51678
>Category:       port-alpha
>Synopsis:       gdb can't run threaded programs
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-alpha-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Dec 01 08:40:00 +0000 2016
>Originator:     Martin Husemann
>Release:        NetBSD 7.99.43
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD gemini.duskware.de 7.99.43 NetBSD 7.99.43 (GENERIC-$Revision: 1.371 $) #34: Tue Nov 29 16:32:43 CET 2016 martin%martins.aprisoft.de@localhost:/ssd/src/sys/arch/alpha/compile/GENERIC alpha
Architecture: alpha
Machine: alpha
>Description:

Trying to run a pthreaded program under gdb fails:

[~] martin@gemini > gdb dig
GNU gdb (GDB) 7.12
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "alpha--netbsd".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from dig...Reading symbols from /usr/libdata/debug//usr/bin/dig.debug...done.
done.
(gdb) run
Starting program: /usr/bin/dig 
[New LWP 4]
[New LWP 3]
[New LWP 2]

Thread 1 received signal SIGTRAP, Trace/breakpoint trap.
[Switching to LWP 1]
0x000003fffd44d968 in _sys___kevent50 () from /usr/lib/libc.so.12


>How-To-Repeat:
s/a

>Fix:
n/a