--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extern/libcompat/src/strndup.c	Sat Dec 05 15:57:02 2020 +0100
@@ -0,0 +1,42 @@
+/*
+ * strndup.c -- strndup implementation
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Requires strnlen. */
+#include "compat.h"
+
+char *
+strndup(const char *src, size_t max)
+{
+	assert(src);
+
+	char *ret;
+	size_t length;
+
+	length = strnlen(src, max);
+
+	if (!(ret = malloc(length + 1)))
+		return NULL;
+
+	ret[length] = '\0';
+
+	return memcpy(ret, src, length);
+}