xC: deal with any identifier conflicts

Invalid UTF-8 converted to UTF-8 may conflict with that
which was valid UTF-8 in the first place.

xC.c

@@ -789,7 +789,7 @@ input_el__redisplay (void *input)
 static char *
 input_el__make_prompt (EditLine *editline)
 {
-	struct input_el *self;
+	struct input_el *self = NULL;
 	el_get (editline, EL_CLIENTDATA, &self);
 	if (!self->prompt)
 		return "";
@@ -1058,8 +1058,13 @@ input_el_buffer_switch (void *input, input_buffer_t input_buffer)
 static void
 input_el_buffer_destroy (void *input, input_buffer_t input_buffer)
 {
-	(void) input;
+	struct input_el *self = input;
 	struct input_el_buffer *buffer = input_buffer;
+	if (self->active && self->current == buffer)
+	{
+		el_wset (self->editline, EL_HIST, history, NULL);
+		self->current = NULL;
+	}
 
 	history_wend (buffer->history);
 	free (buffer->saved_line);
@@ -4349,6 +4354,10 @@ buffer_print_read_marker (struct app_context *ctx, FILE *stream, int flush_opts)
 static void
 buffer_print_backlog (struct app_context *ctx, struct buffer *buffer)
 {
+	// Buffers can be activated, or their lines modified, as automatic actions.
+	if (ctx->terminal_suspended)
+		return;
+
 	// The prompt can take considerable time to redraw
 	CALL (ctx->input, hide);
 
@@ -4613,11 +4622,24 @@ irc_make_buffer_name (struct server *s, const char *target)
 	if (!target)
 		return xstrdup (s->name);
 
-	// XXX: this may be able to trigger the uniqueness assertion with non-UTF-8
 	char *target_utf8 = irc_to_utf8 (target);
-	char *result = xstrdup_printf ("%s.%s", s->name, target_utf8);
+	char *name = xstrdup_printf ("%s.%s", s->name, target_utf8);
 	free (target_utf8);
-	return result;
+
+	struct buffer *conflict = buffer_by_name (s->ctx, name);
+	if (!conflict)
+		return name;
+
+	hard_assert (conflict->server == s);
+
+	// Fix up any conflicts.  Note that while parentheses aren't allowed
+	// in IRC nicknames, they may occur in channel names.
+	int i = 0;
+	char *unique = xstrdup_printf ("%s(%d)", name, ++i);
+	while (buffer_by_name (s->ctx, unique))
+		cstr_set (&unique, xstrdup_printf ("%s(%d)", name, ++i));
+	free (name);
+	return unique;
 }
 
 static void
@@ -11269,6 +11291,7 @@ handle_command_buffer (struct handler_args *a)
 	else if (!strcasecmp_ascii (action, "clear"))
 	{
 		buffer_clear (a->buffer);
+		if (a->buffer == ctx->current_buffer)
 			buffer_print_backlog (ctx, a->buffer);
 	}
 	else if (!strcasecmp_ascii (action, "move"))