--- scd/app.c	2024-10-15 19:40:56.000000000 +0800
+++ scd/app.c	2024-11-07 21:02:37.000000000 +0800
@@ -22,6 +22,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <npth.h>
 
 #ifndef HAVE_W32_SYSTEM