w(1) uses strftime %b with to print the abbreviated month name

if a user logged in more than a week ago.
This may contain multibyte characters (e.g. when using UTF-8).
This string is then aligned on byte-length rathern than char-length,
resulting in misalignment and unfinished multibyte characters.

PR:             126657
Submitted by:   Johan van Selst <johans@stack.nl>

usr.bin/w/pr_time.c

@@ -44,6 +44,7 @@ static const char sccsid[] = "@(#)pr_time.c	8.2 (Berkeley) 4/4/94";
 
 #include <stdio.h>
 #include <string.h>
+#include <wchar.h>
 
 #include "extern.h"
 
@@ -82,7 +83,7 @@ pr_attime(time_t *started, time_t *now)
 	}
 
 	(void)strftime(buf, sizeof(buf), fmt, &tp);
-	(void)printf("%-7.7s", buf);
+	(void)wprintf(L"%-7.7s", buf);
 }
 
 /*