diff -Naur a/7plus.h b/7plus.h
--- a/7plus.h	2000-01-10 10:03:02.000000000 +0000
+++ b/7plus.h	2022-02-13 21:16:05.186445213 +0000
@@ -24,6 +24,8 @@
 /* #define setvbuf(a,b,c,d) */
 
 /** these includes should work anywhere **/
+#include <unistd.h>
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <time.h>