xvasprintf (&linebuffer, format, args);
linebuffer = xstrvprintf (format, args);
vfprintf_maybe_filtered (struct ui_file *stream, const char *format,			 va_list args, int filter){  char *linebuffer;  struct cleanup *old_cleanups;  xvasprintf (&linebuffer, format, args);  old_cleanups = make_cleanup (xfree, linebuffer);  fputs_maybe_filtered (linebuffer, stream, filter);  do_cleanups (old_cleanups);}