--- mfhdf/libsrc/file.c.orig	2020-03-04 02:40:50.000000000 +0900
+++ mfhdf/libsrc/file.c	2020-11-21 20:28:41.000000000 +0900
@@ -20,6 +20,7 @@
 #include <assert.h>
 #endif /* DEBUG */
 
+#include    <unistd.h>
 #include    <string.h>
 #include    <errno.h>
 #include    "local_nc.h"