diff -pNaru5 a/src/trans.c b/src/trans.c
--- a/src/trans.c	2015-10-02 13:52:53.000000000 -0400
+++ b/src/trans.c	2022-12-25 21:43:08.603410698 -0500
@@ -18,10 +18,11 @@ the Free Software Foundation, Inc., 675
 
 
 
 #define define_globals
 #define PROTO_TRANS_C
+#include <unistd.h>
 #include "trans.h"
 
 #include <time.h>
 
 
diff -pNaru5 a/src/trans.h b/src/trans.h
--- a/src/trans.h	2015-10-05 19:04:46.000000000 -0400
+++ b/src/trans.h	2022-12-25 21:52:49.184033191 -0500
@@ -1861,12 +1861,14 @@ extern Expr *new_array_size;
 
 
 
 /* Our library omits declarations for these functions! */
 
+/*
 int link           PP( (char *, char *) );
 int unlink         PP( (char *) );
+*/
 
 
 
 #define minspcthresh ((minspacingthresh >= 0) ? minspacingthresh : minspacing)