rem: size_t len;  len = strlen (dir_name);
add: size_t len = strlen (dir_name);
context: push_dir (Dirstack_state *ds, const char *dir_name){  size_t len;  len = strlen (dir_name);  /* Append the string onto the stack.  */  obstack_grow (&ds->dir_stack, dir_name, len);  /* Append a trailing slash.  */  obstack_1grow (&ds->dir_stack, '/');  /* Add one for the slash.  */  ++len;  /* Push the length (including slash) onto its stack.  */  obstack_grow (&ds->len_stack, &len, sizeof (len));}