Clear destination char when converting from wchar_t or the result could

include stack garbage. GitHub issue 5792 from hrajyw4 at gmail dot com.

utf8.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: utf8.c,v 1.75 2026/10/13 10:21:58 nicm Exp $ */
+/* $OpenBSD: utf8.c,v 1.76 2026/10/23 06:30:50 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -667,6 +667,8 @@ utf8_fromwc(wchar_t wc, struct utf8_data *ud)
 {
 	int	size, width;
 
+	memset(ud, 0, sizeof *ud);
+
 	size = wctomb(ud->data, wc);
 	if (size < 0) {
 		log_debug("UTF-8 %d, wctomb() %d", wc, errno);