Fix:

error: implicit declaration of function 'close' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
error: implicit declaration of function 'host_statistics' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
error: implicit declaration of function 'mach_host_self' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
error: implicit declaration of function 'sleep' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
error: implicit declaration of function 'umask' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
--- stats-mach.c.orig	2003-05-27 02:03:43.000000000 -0500
+++ stats-mach.c	2024-08-02 18:52:45.000000000 -0500
@@ -37,10 +37,8 @@
 /*@unused@*/ static const char rcsid[] =
     "@(#)$Id: stats-mach.c,v 1.15 2003/05/26 19:54:04 carstenklapp Exp $";
 
-                                                    /* #include <mach/mach.h> *//* replaced by following
-                                                       two lines */
-#include <mach/host_info.h>
-#include <mach/error.h>
+#include <mach/mach.h>
+#include <unistd.h>
 #include "uplog.h"
 #include "stats.h"
 
--- transmit.c.orig	2003-05-27 02:03:43.000000000 -0500
+++ transmit.c	2024-08-02 18:54:55.000000000 -0500
@@ -38,6 +38,7 @@
 #include <netdb.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 
 #if defined __NetBSD__
 #   include <sys/socket.h>
--- upclient.c.orig	2003-05-27 02:03:43.000000000 -0500
+++ upclient.c	2024-08-02 18:57:04.000000000 -0500
@@ -36,7 +36,8 @@
 /* Common system includes */
 #include <stdio.h>
 
-/*#include <stdlib.h>*/
+#include <stdlib.h>
+#include <sys/stat.h>
 #include <errno.h>
 #include <string.h>