there are no `pw_fields` in `struct passwd` under openbsd

src/unix/bsd/mod.rs

@@ -43,7 +43,8 @@ s! {
 
         #[cfg(not(any(target_os = "macos",
                       target_os = "ios",
-                      target_os = "netbsd")))]
+                      target_os = "netbsd",
+                      target_os = "openbsd")))]
         pub pw_fields: ::c_int,
     }