standards/58608: C23: <time.h> timespec_getres, timegm, TIME_*

[campbell+netbsd%mumble.net@localhost]

>Number:         58608
>Category:       standards
>Synopsis:       C23: <time.h> timespec_getres, timegm, TIME_*
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    standards-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 16 11:10:00 +0000 2024
>Originator:     Taylor R Campbell
>Release:        current, 10, 9
>Organization:
The NetBSD time23_t Foundation
>Environment:
>Description:
C23 7.29: Date and time <time.h>

https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3096.pdf#page=417

New timespec_get bases:
- TIME_MONOTONIC
- TIME_ACTIVE
- TIME_THREAD_ACTIVE

New functions:
- time_t timegm(struct tm *timeptr); (newly standard, needs visibility outside _NETBSD_SOURCE)
- int timespec_getres(struct timespec *ts, int base);

>How-To-Repeat:
standards inspection
>Fix:
Yes, please!