default md5.h to define function prototypes

Author: bernstei

src/libAtoms/md5.h

@@ -24,7 +24,7 @@ typedef uint32_t UINT4;
 If using PROTOTYPES, then PROTO_LIST returns the list, otherwise it
   returns an empty list.
  */
-#if PROTOTYPES
+#ifndef NO_PROTOTYPES
 #define PROTO_LIST(list) list
 #else
 #define PROTO_LIST(list) ()