Merge branch 'lm/squelch-bg-progress'

The controlling tty-based heuristics to squelch progress output did
not consider that the process may not be talking to a tty at all
(e.g. sending the progress to sideband #2).  This is a finishing
touch to a topic that is already in 'master'.

* lm/squelch-bg-progress:
  progress: treat "no terminal" as being in the foreground

progress.c

@@ -74,7 +74,8 @@ static void clear_progress_signal(void)
 
 static int is_foreground_fd(int fd)
 {
-	return getpgid(0) == tcgetpgrp(fd);
+	int tpgrp = tcgetpgrp(fd);
+	return tpgrp < 0 || tpgrp == getpgid(0);
 }
 
 static int display(struct progress *progress, unsigned n, const char *done)