Needed to get the bzero() declaration.

--- hplip-3.25.6/io/hpmud/jd.c.orig
+++ hplip-3.25.6/io/hpmud/jd.c
@@ -31,6 +31,7 @@
 #endif
 
 #include <signal.h>
+#include <strings.h>
 #include "hpmud.h"
 #include "hpmudi.h"