Reapply "Mypy: Got passing on macos (#34591)" (#35126)

* Mypy: Got passing on macos (#34591)

* Mypy: Got mypy passing on macos

* common/realtime.py refactor

* Mypy: mypy passing on darwin

* Refactor: Removed else: pass statement

* Refactor: Removed unnecessary check

* added xattr to pyproject

* loggerd: switched to xatter module

* loggerd: removed unused module in xattr_cache.py

* UV: update uv.lock

* Update system/athena/athenad.py

Co-authored-by: Maxime Desroches <desroches.maxime@gmail.com>

* athenad: fixed blank lines

* loggerd: refactor of xattr_cache

* cleanup

---------

Co-authored-by: Maxime Desroches <desroches.maxime@gmail.com>

* fix getxattr no attribute on macOS

* try fixing missing ENOATTR on Linux

---------

Co-authored-by: BrainLess <116778989+BrainLessPea@users.noreply.github.com>
Co-authored-by: Maxime Desroches <desroches.maxime@gmail.com>

common/realtime.py

@@ -1,6 +1,7 @@
 """Utilities for reading real time clocks and keeping soft real time constraints."""
 import gc
 import os
+import sys
 import time
 
 from setproctitle import getproctitle
@@ -28,13 +29,13 @@ class Priority:
 
 
 def set_core_affinity(cores: list[int]) -> None:
-  if not PC:
+  if sys.platform == 'linux' and not PC:
     os.sched_setaffinity(0, cores)
 
 
 def config_realtime_process(cores: int | list[int], priority: int) -> None:
   gc.disable()
-  if not PC:
+  if sys.platform == 'linux' and not PC:
     os.sched_setscheduler(0, os.SCHED_FIFO, os.sched_param(priority))
   c = cores if isinstance(cores, list) else [cores, ]
   set_core_affinity(c)