diff --git a/games/adventure/done.c b/games/adventure/done.c
index 3dd013a3019..f76961321af 100644
--- a/games/adventure/done.c
+++ b/games/adventure/done.c
@@ -47,6 +47,7 @@ static const char rcsid[] =
 /*      Re-coding of advent in C: termination routines                  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include "hdr.h"
 
 int
diff --git a/games/adventure/main.c b/games/adventure/main.c
index 8b21937de11..5b67d7bba1c 100644
--- a/games/adventure/main.c
+++ b/games/adventure/main.c
@@ -57,6 +57,7 @@ static const char rcsid[] =
 #include <sys/types.h>
 #include <signal.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include "hdr.h"
diff --git a/games/adventure/subr.c b/games/adventure/subr.c
index 6bbb57e3af8..d1474125b2b 100644
--- a/games/adventure/subr.c
+++ b/games/adventure/subr.c
@@ -47,6 +47,7 @@ static const char rcsid[] =
 /*      Re-coding of advent in C: subroutines from main                 */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include "hdr.h"