diff --git a/ChangeLog b/ChangeLog
index 8963152166..715acc66ab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-04-28  Joseph Myers  <joseph@codesourcery.com>
+
+	* libio/stdio.h (off_t): Also define if [__USE_UNIX98].
+	[__USE_LARGEFILE64] (off64_t): Likewise.
+	* conform/Makefile (test-xfail-UNIX98/stdio.h/conform): Remove
+	variable.
+
 2016-04-28  Florian Weimer  <fweimer@redhat.com>
 
 	* inet/getnameinfo.c (getnameinfo): Do not preserve errno.
diff --git a/conform/Makefile b/conform/Makefile
index 26264fc96d..7665f77781 100644
--- a/conform/Makefile
+++ b/conform/Makefile
@@ -202,7 +202,6 @@ test-xfail-UNIX98/langinfo.h/conform = yes
 test-xfail-UNIX98/netdb.h/conform = yes
 test-xfail-UNIX98/netinet/in.h/conform = yes
 test-xfail-UNIX98/signal.h/conform = yes
-test-xfail-UNIX98/stdio.h/conform = yes
 test-xfail-UNIX98/stdlib.h/conform = yes
 test-xfail-UNIX98/sys/time.h/conform = yes
 test-xfail-UNIX98/sys/wait.h/conform = yes
diff --git a/libio/stdio.h b/libio/stdio.h
index d7dbfad53b..712b9949e1 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -84,7 +84,7 @@ typedef _G_va_list va_list;
 # endif
 #endif
 
-#ifdef __USE_XOPEN2K
+#if defined __USE_UNIX98 || defined __USE_XOPEN2K
 # ifndef __off_t_defined
 # ifndef __USE_FILE_OFFSET64
 typedef __off_t off_t;