--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/compat/asprintf.c	Thu Jan 19 22:39:51 2017 +0100
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2015 Guido Berhoerster <guido+pwm@berhoerster.name>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include "asprintf.h"
+
+int
+vasprintf(char **strp, const char *fmt, va_list args)
+{
+	int	len;
+	va_list	args_new;
+	char	*str;
+
+	*strp = NULL;
+	va_copy(args_new, args);
+
+	len = vsnprintf(NULL, 0, fmt, args);
+	if (len < 0) {
+		goto out;
+	}
+
+	str = malloc(len + 1);
+	if (str == NULL) {
+		goto out;
+	}
+	len = vsnprintf(str, len + 1, fmt, args_new);
+	if (len < 0) {
+		free(str);
+		goto out;
+	}
+	*strp = str;
+out:
+	va_end(args_new);
+
+	return (len);
+}
+
+int
+asprintf(char **strp, const char *fmt, ...)
+{
+	int	len;
+	va_list	args;
+
+	va_start(args, fmt);
+	len = vasprintf(strp, fmt, args);
+	va_end(args);
+
+	return (len);
+}