diff -Naur gkermit/gkermit.c gkermit-fixed/gkermit.c
--- gkermit/gkermit.c	2021-11-15 17:56:42.000000000 +0300
+++ gkermit-fixed/gkermit.c	2024-12-21 18:53:48.016896984 +0300
@@ -87,6 +87,7 @@
 
 #define _GKERMIT_C
 #include <stdio.h>
+#include <unistd.h>
 #include "gkermit.h"
 
 /* Forward declarations of functions used within this module... */
diff -Naur gkermit/gunixio.c gkermit-fixed/gunixio.c
--- gkermit/gunixio.c	2021-11-15 17:50:09.000000000 +0300
+++ gkermit-fixed/gunixio.c	2024-12-21 18:55:55.486884839 +0300
@@ -84,6 +84,7 @@
 #include <setjmp.h>			/* Longjumps */
 #include <sys/stat.h>			/* File exist, file size */
 #include <errno.h>			/* Error symbols */
+#include <unistd.h>			/* write, read, alarm, other stuff */ 
 #include "gkermit.h"			/* gkermit definitions */
 
 /* All versions of HP-UX need Xon/Xoff */