diff --git a/lib/decode_rs.c b/lib/decode_rs.c
index ac85eddd7..53b441d39 100644
--- a/lib/decode_rs.c
+++ b/lib/decode_rs.c
@@ -7,9 +7,9 @@
 #include <stdio.h>
 #endif
 
+#include <stdlib.h>
 #include <string.h>
 
-//#define NULL ((void *)0)
 #define	min(a,b)	((a) < (b) ? (a) : (b))
 
 #ifdef FIXED
diff --git a/lib/ftrsd/decode_rs.c b/lib/ftrsd/decode_rs.c
index daeaaaebf..990b687ac 100644
--- a/lib/ftrsd/decode_rs.c
+++ b/lib/ftrsd/decode_rs.c
@@ -8,6 +8,7 @@
 #include <stdio.h>
 #endif
 
+#include <stdlib.h>
 #include <string.h>
 
 #define	min(a,b)	((a) < (b) ? (a) : (b))
diff --git a/lib/init_rs.c b/lib/init_rs.c
index b836c1c53..a80523651 100644
--- a/lib/init_rs.c
+++ b/lib/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;
 
diff --git a/lib/vit213.c b/lib/vit213.c
index 616a2fd81..93f803abb 100644
--- a/lib/vit213.c
+++ b/lib/vit213.c
@@ -5,6 +5,8 @@
  * May be used under the terms of the GNU Public License
  */
 
+#include <stdlib.h>
+
 /* Select code here */
 
 #define V213
diff --git a/lib/vit216.c b/lib/vit216.c
index 38984d2f4..fc0c5a761 100644
--- a/lib/vit216.c
+++ b/lib/vit216.c
@@ -18,8 +18,8 @@
 /* Rate 1/2 codes */
 unsigned int Poly216[] = {0126723, 0152711};	/* k = 16  */
 
+#include <stdlib.h>
 #include <memory.h>
-#define NULL ((void *)0)
 
 #define LONGBITS 32
 #define LOGLONGBITS 5