diff --git a/usr.bin/gencat/gencat.c b/usr.bin/gencat/gencat.c
index 7c9a8e0370b..37c79909301 100644
--- a/usr.bin/gencat/gencat.c
+++ b/usr.bin/gencat/gencat.c
@@ -42,6 +42,7 @@ up-to-date.  Many thanks.
 
 #include <stdio.h>
 #include <sys/types.h>
+#include <unistd.h>
 #ifdef SYSV
 #include <sys/fcntl.h>
 #define L_SET SEEK_SET
diff --git a/usr.bin/gencat/genlib.c b/usr.bin/gencat/genlib.c
index 30275f1db4d..f592be003c1 100644
--- a/usr.bin/gencat/genlib.c
+++ b/usr.bin/gencat/genlib.c
@@ -42,9 +42,9 @@ up-to-date.  Many thanks.
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#ifdef SYSV
 #include <sys/types.h>
 #include <unistd.h>
+#ifdef SYSV
 #define L_SET SEEK_SET
 #define L_INCR SEEK_CUR
 #include <memory.h>