--- a/util.c	Wed Feb 05 20:10:00 2020 +0100
+++ b/util.c	Wed Feb 05 13:15:55 2020 +0100
@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <stdnoreturn.h>
 #include <string.h>
+#include <time.h>
 
 #include "util.h"
 
@@ -64,3 +65,13 @@
 
 	return buf;
 }
+
+const char *
+bstrftime(const char *fmt, const struct tm *tm)
+{
+	static char buf[BUFSIZ];
+
+	strftime(buf, sizeof (buf), fmt, tm);
+
+	return buf;
+}