lib/58391: re-adding syslog_ss() to syslog.h and syslog.3

[soda%NetBSD.org@localhost]

>Number:         58391
>Category:       lib
>Synopsis:       re-adding syslog_ss() to syslog.h and syslog.3
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 02 04:30:00 +0000 2024
>Originator:     Noriyuki Soda
>Release:        NetBSD 9.2
>Organization:
	the NetBSD project
>Environment:
System: NetBSD bruce 9.2 NetBSD 9.2 (GENERIC) #0: Wed May 12 13:15:55 UTC 2021 mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:

There is syslog_ss() function -- async-signal-safe variant of syslog() --
in our libc, but it's not defined in syslog.h and syslog.3 man page.
I believe that the reason it hasn't been defined there was
compatibility concern:
http://mail-index.netbsd.org/tech-userlevel/2006/10/27/0004.html

But because it's more than 16 years since it was implemented,
I think it's time to define them now.

>How-To-Repeat:

see syslog.h and syslog.3 man page.

>Fix:

backout the following changes:
syslog.h revision 1.30
syslog.3 revision 1.24