tree-wide: introduce strerror_safe()

src/core/socket.c

@@ -782,7 +782,7 @@ static void socket_dump(Unit *u, FILE *f, const char *prefix) {
 
                         r = socket_address_print(&p->address, &k);
                         if (r < 0)
-                                t = strerror(-r);
+                                t = strerror_safe(r);
                         else
                                 t = k;