added unbound to external deps

external/unbound/compat/malloc.c

@@ -0,0 +1,19 @@
+/* Just a replacement, if the original malloc is not
+   GNU-compliant. See autoconf documentation. */
+
+#include "config.h"
+#undef malloc
+#include <sys/types.h>
+
+void *malloc ();
+
+/* Allocate an N-byte block of memory from the heap.
+   If N is zero, allocate a 1-byte block.  */
+
+void *
+rpl_malloc_unbound (size_t n)
+{
+  if (n == 0)
+    n = 1;
+  return malloc (n);
+}