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