--- mfhdf/test/tsd.c.orig	2020-03-04 02:40:50.000000000 +0900
+++ mfhdf/test/tsd.c	2020-11-22 05:53:43.000000000 +0900
@@ -15,6 +15,7 @@
  * tsd.c - tests SDstart for file with no write permission
 ****************************************************************************/
 
+#include <unistd.h>
 #include "mfhdf.h"
 
 #ifdef HDF