fix(build): adjust Linux-only header after 5cb9c3c

In file included from theseus-ship-6.0.0/main_wayland.cpp:10:
In file included from /usr/include/como/base/wayland/xwl_platform.h:17:
In file included from /usr/include/como/render/wayland/xwl_platform.h:15:
In file included from /usr/include/como/render/post/night_color_manager.h:14:
/usr/include/como/base/os/clock/skew_notifier.h:8:10: fatal error: 'skew_notifier_engine.h' file not found
    8 | #include "skew_notifier_engine.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~

como/base/CMakeLists.txt

@@ -18,7 +18,7 @@ target_sources(base
   PUBLIC
     FILE_SET HEADERS
     FILES
-      os/clock/linux_skew_notifier_engine.h
+      os/clock/skew_notifier_engine.h
       os/clock/skew_notifier.h
       seat/backend/logind/session.h
       seat/session.h
@@ -49,7 +49,7 @@ if (CMAKE_SYSTEM_NAME MATCHES "Linux")
     PUBLIC
       FILE_SET HEADERS
       FILES
-        os/clock/skew_notifier_engine.h
+        os/clock/linux_skew_notifier_engine.h
     PRIVATE
       os/clock/linux_skew_notifier_engine.cpp
   )