[Bug lto/60295] [4.9 Regression] Too many lto1-wpa-stream processes are forked

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60295

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
-flto=jobserver is added by bootstrap-lto.mk.  There are

static void 
stream_out (char *temp_filename, lto_symtab_encoder_t encoder, bool last)
{
#ifdef HAVE_WORKING_FORK
  static int nruns;

  if (!lto_parallelism || lto_parallelism == 1)
    {    
      do_stream_out (temp_filename, encoder);
      return;
    }    

  /* Do not run more than LTO_PARALLELISM streamings
     FIXME: we ignore limits on jobserver.  */
  if (lto_parallelism > 0 && nruns >= lto_parallelism)
    {    
      wait_for_child ();
      nruns --;
    }
...
  /* TODO: jobserver communicatoin is not supported, yet.  */
  if (!strcmp (flag_wpa, "jobserver"))
    lto_parallelism = -1;
  else
    {
      lto_parallelism = atoi (flag_wpa);
      if (lto_parallelism <= 0)
        lto_parallelism = 0;
    }

I would assume lto_parallelism == -1.