diff --git a/libs/diskusage/dirsize.c b/libs/diskusage/dirsize.c
index 24e5af02a..7576994c0 100644
--- a/libs/diskusage/dirsize.c
+++ b/libs/diskusage/dirsize.c
@@ -18,6 +18,7 @@
 #include <dirent.h>
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include <diskusage/dirsize.h>