diff --git a/openbsd-compat/bsd-err.c b/openbsd-compat/bsd-err.c
index ab10646f0..e4ed22b86 100644
--- a/openbsd-compat/bsd-err.c
+++ b/openbsd-compat/bsd-err.c
@@ -27,6 +27,12 @@
 
 #include "includes.h"
 
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
 #ifndef HAVE_ERR
 void
 err(int r, const char *fmt, ...)