xC: fix newer Readline, allow stdin streaming

Also update NEWS.

xC.c

@@ -474,6 +474,10 @@ input_rl_start (void *input, const char *program_name)
 	// autofilter, and we don't generally want alphabetic ordering at all
 	rl_sort_completion_matches = false;
 
+	// Readline >= 8.0 otherwise prints spurious newlines on EOF.
+	if (RL_VERSION_MAJOR >= 8)
+		rl_variable_bind ("enable-bracketed-paste", "off");
+
 	hard_assert (self->prompt != NULL);
 	// The inputrc is read before any callbacks are called, so we need to
 	// register all functions that our user may want to map up front
@@ -14603,21 +14607,23 @@ on_readline_input (char *line)
 		if (*line)
 			add_history (line);
 
-		// readline always erases the input line after returning from here,
+		// Readline always erases the input line after returning from here,
 		// but we don't want that to happen if the command to be executed
 		// would switch the buffer (we'd keep the already executed command in
 		// the old buffer and delete any input restored from the new buffer)
 		strv_append_owned (&ctx->pending_input, line);
 		poller_idle_set (&ctx->input_event);
 	}
-	else
+	else if (isatty (STDIN_FILENO))
 	{
-		// Prevent readline from showing the prompt twice for w/e reason
+		// Prevent Readline from showing the prompt twice for w/e reason
 		CALL (ctx->input, hide);
 		input_rl__restore (self);
 
 		CALL (ctx->input, ding);
 	}
+	else
+		request_quit (ctx, NULL);
 
 	if (self->active)
 		// Readline automatically redisplays it