Merge branch 'pw/single-key-interactive'

The single-key interactive operation used by "git add -p" has been
made more robust.

* pw/single-key-interactive:
  add -p: disable stdin buffering when interactive.singlekey is set
  terminal: set VMIN and VTIME in non-canonical mode
  terminal: pop signal handler when terminal is restored
  terminal: always reset terminal when reading without echo

add-interactive.c

@@ -70,6 +70,8 @@ void init_add_i_state(struct add_i_state *s, struct repository *r)
 			      &s->interactive_diff_algorithm);
 
 	git_config_get_bool("interactive.singlekey", &s->use_single_key);
+	if (s->use_single_key)
+		setbuf(stdin, NULL);
 }
 
 void clear_add_i_state(struct add_i_state *s)