port-sparc64/59313: t_sig_backtrace tests are failing

[campbell+netbsd%mumble.net@localhost]

>Number:         59313
>Category:       port-sparc64
>Synopsis:       t_sig_backtrace tests are failing
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-sparc64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 17 14:15:00 +0000 2025
>Originator:     Taylor R Campbell
>Release:        current
>Organization:
The sigsparcBacktraceD Foundation
>Environment:
>Description:
On sparc:

FAILED: /tmp/build/2025.04.16.12.05.52-sparc/src/tests/lib/libexecinfo/t_sig_backtrace.c:176: found_the_loop not met
Standard output stream

signal: 11
Backtrace 2 stack frames.
0x10e28 <handler+0x20> at /usr/tests/lib/libexecinfo/t_sig_backtrace
0xedd82544 <__sigtramp_siginfo_2> at /usr/lib/libc.so.12

https://releng.netbsd.org/b5reports/sparc/2025/2025.04.16.12.05.52/test.html#lib_libexecinfo_t_sig_backtrace_sig_backtrace_deref

On sparc64:

FAILED: /tmp/build/2025.04.16.12.05.52-sparc64/src/tests/lib/libexecinfo/t_sig_backtrace.c:175: found_sigtramp not met
Standard output stream

signal: 11
Backtrace 1 stack frames.
0x101b14 <handler+0x100034> at /usr/tests/lib/libexecinfo/t_sig_backtrace

So stack traces through signal handlers are missing something.
>How-To-Repeat:
cd /usr/tests/lib/libexecinfo
atf-run t_sig_backtrace | atf-report
>Fix:
Yes, please!