diff --git a/src/include/dirent.h b/src/include/dirent.h
index f5301cbb..920421b5 100644
--- a/src/include/dirent.h
+++ b/src/include/dirent.h
@@ -38,6 +38,13 @@
 #ifndef _DIRENT_H_
 #define _DIRENT_H_
 
+/*
+ * POSIX doesn't mandate this, but X/Open XPG 4.2 does.
+ */
+#ifndef _POSIX_SOURCE
+#include <sys/types.h>
+#endif
+
 /*
  * The kernel defines the format of directory entries returned by 
  * the getdirentries(2) system call.