only set process title on Linux

the systemcall is not portable

pkgs/clan-vm-manager/clan_vm_manager/executor.py

@@ -38,6 +38,8 @@ class MPProcess:
 
 
 def _set_proc_name(name: str) -> None:
+    if sys.platform != "linux":
+        return
     import ctypes
 
     # Define the prctl function with the appropriate arguments and return type