Clean up some compiler warnings

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6591 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/ftrsd/decode_rs.c

@@ -10,7 +10,6 @@
 
 #include <string.h>
 
-#define NULL ((void *)0)
 #define	min(a,b)	((a) < (b) ? (a) : (b))
 
 #ifdef FIXED

lib/ftrsd/init_rs.c

@@ -13,8 +13,6 @@
 #include "char.h"
 #endif
 
-#define NULL ((void *)0)
-
 void FREE_RS(void *p){
   struct rs *rs = (struct rs *)p;