diff --git a/lib/roken/strdup.c b/lib/roken/strdup.c
new file mode 100644
index 000000000..146d1ea8b
--- /dev/null
+++ b/lib/roken/strdup.c
@@ -0,0 +1,12 @@
+#include "bsd_locl.h"
+
+#ifndef HAVE_STRDUP
+static char *
+strdup(const char *old)
+{
+	char *t = malloc(strlen(old)+1);
+	if (t != 0)
+		strcpy(t, old);
+	return t;
+}
+#endif