--- Source/troff_generator.c.orig	2011-02-02 23:45:37.000000000 +0100
+++ Source/troff_generator.c    2021-07-27 17:48:02.000000000 +0200
@@ -30,7 +30,7 @@
 #include <ctype.h>
 
 #include <sys/param.h>
-#include <sys/unistd.h>
+#include <unistd.h>
 
 #include "troff_generator.h"
 #include "util.h"