doc: posix: add posix timers and clock selection

Update the POSIX API documentation with details on
POSIX_TIMERS and POSIX_CLOCK_SELECTION.

(cherry picked from commit b0a3736)

Original-Signed-off-by: Christopher Friedt <cfriedt@meta.com>
GitOrigin-RevId: b0a3736
Change-Id: Idb8e0baa5dcaa619c6803d0d741cf26b928b8f7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/4921896
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: Keith Short <keithshort@chromium.org>
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>

doc/services/portability/posix.rst

@@ -85,11 +85,11 @@ Zephyr.
  :widths: 50,10
 
  _POSIX_BARRIERS,yes
- _POSIX_CLOCK_SELECTION,
+ _POSIX_CLOCK_SELECTION,yes
  _POSIX_FSYNC,
  _POSIX_MEMLOCK,
  _POSIX_MEMLOCK_RANGE,
- _POSIX_MONOTONIC_CLOCK,
+ _POSIX_MONOTONIC_CLOCK,yes
  _POSIX_NO_TRUNC,
  _POSIX_REALTIME_SIGNALS,
  _POSIX_SEMAPHORES,yes
@@ -104,7 +104,7 @@ Zephyr.
  _POSIX_THREAD_PRIORITY_SCHEDULING,yes
  _POSIX_THREAD_SPORADIC_SERVER,
  _POSIX_TIMEOUTS,
- _POSIX_TIMERS,
+ _POSIX_TIMERS,yes
  _POSIX2_C_DEV,
  _POSIX2_SW_DEV,
 
@@ -453,3 +453,31 @@ POSIX_DEVICE_IO
  vprintf(),yes
  vscanf(),
  write(),yes
+
+POSIX_TIMERS
+++++++++++++
+
+.. csv-table:: POSIX_TIMERS
+ :header: API, Supported
+ :widths: 50,10
+
+ clock_getres(),
+ clock_gettime(),yes
+ clock_settime(),yes
+ nanosleep(),yes
+ timer_create(),yes
+ timer_delete(),yes
+ timer_gettime(),yes
+ timer_getoverrun(),yes
+ timer_settime(),yes
+
+POSIX_CLOCK_SELECTION
++++++++++++++++++++++
+
+.. csv-table:: POSIX_CLOCK_SELECTION
+ :header: API, Supported
+ :widths: 50,10
+
+ pthread_condattr_getclock(),yes
+ pthread_condattr_setclock(),yes
+ clock_nanosleep(),yes