chore(3p/nix): Clean up some unused defines

third_party/nix/src/libstore/remote-store.cc

@@ -90,13 +90,7 @@ ref<RemoteStore::Connection> UDSRemoteStore::openConnection() {
   auto conn = make_ref<Connection>();
 
   /* Connect to a daemon that does the privileged work for us. */
-  conn->fd = socket(PF_UNIX,
-                    SOCK_STREAM
-#ifdef SOCK_CLOEXEC
-                        | SOCK_CLOEXEC
-#endif
-                    ,
-                    0);
+  conn->fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
   if (!conn->fd) {
     throw SysError("cannot create Unix domain socket");
   }