Add os.unshare clone flags for Linux, Python 3.12+ (#10757)

stdlib/os/__init__.pyi

@@ -1056,3 +1056,19 @@ if sys.version_info >= (3, 12) and sys.platform == "win32":
     def listdrives() -> list[str]: ...
     def listmounts(volume: str) -> list[str]: ...
     def listvolumes() -> list[str]: ...
+
+if sys.version_info >= (3, 12) and sys.platform == "linux":
+    CLONE_FILES: int
+    CLONE_FS: int
+    CLONE_NEWCGROUP: int
+    CLONE_NEWIPC: int
+    CLONE_NEWNET: int
+    CLONE_NEWNS: int
+    CLONE_NEWPID: int
+    CLONE_NEWTIME: int
+    CLONE_NEWUSER: int
+    CLONE_NEWUTS: int
+    CLONE_SIGHAND: int
+    CLONE_SYSVSEM: int
+    CLONE_THREAD: int
+    CLONE_VM: int

stdlib/posix.pyi

@@ -314,6 +314,24 @@ if sys.platform != "win32":
     if sys.platform != "darwin":
         from os import RWF_DSYNC as RWF_DSYNC, RWF_HIPRI as RWF_HIPRI, RWF_NOWAIT as RWF_NOWAIT, RWF_SYNC as RWF_SYNC
 
+    if sys.version_info >= (3, 12) and sys.platform == "linux":
+        from os import (
+            CLONE_FILES as CLONE_FILES,
+            CLONE_FS as CLONE_FS,
+            CLONE_NEWCGROUP as CLONE_NEWCGROUP,
+            CLONE_NEWIPC as CLONE_NEWIPC,
+            CLONE_NEWNET as CLONE_NEWNET,
+            CLONE_NEWNS as CLONE_NEWNS,
+            CLONE_NEWPID as CLONE_NEWPID,
+            CLONE_NEWTIME as CLONE_NEWTIME,
+            CLONE_NEWUSER as CLONE_NEWUSER,
+            CLONE_NEWUTS as CLONE_NEWUTS,
+            CLONE_SIGHAND as CLONE_SIGHAND,
+            CLONE_SYSVSEM as CLONE_SYSVSEM,
+            CLONE_THREAD as CLONE_THREAD,
+            CLONE_VM as CLONE_VM,
+        )
+
     # Not same as os.environ or os.environb
     # Because of this variable, we can't do "from posix import *" in os/__init__.pyi
     environ: dict[bytes, bytes]