diff --git a/nt/ChangeLog b/nt/ChangeLog
index 10f145a0dd9..031735edac8 100644
--- a/nt/ChangeLog
+++ b/nt/ChangeLog
@@ -1,5 +1,11 @@
 2013-03-26  Eli Zaretskii  <eliz@gnu.org>
 
+	* addsection.c (_ANONYMOUS_UNION, _ANONYMOUS_STRUCT): Do not
+	define for MinGW64.
+
+	* preprep.c (_ANONYMOUS_UNION, _ANONYMOUS_STRUCT): Do not define
+	for MinGW64.
+
 	Fix more incompatibilities between MinGW.org and MinGW64 headers
 	reported by Óscar Fuentes in
 	http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00733.html
diff --git a/nt/addsection.c b/nt/addsection.c
index ee68ebee9b2..61a8cfce742 100644
--- a/nt/addsection.c
+++ b/nt/addsection.c
@@ -25,7 +25,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdio.h>
 #include <fcntl.h>
 #include <time.h>
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(_W64)
 #define _ANONYMOUS_UNION
 #define _ANONYMOUS_STRUCT
 #endif
diff --git a/nt/preprep.c b/nt/preprep.c
index 8604dd40c1f..42855ce7f20 100644
--- a/nt/preprep.c
+++ b/nt/preprep.c
@@ -25,7 +25,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdio.h>
 #include <fcntl.h>
 #include <time.h>
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(_W64)
 #define _ANONYMOUS_UNION
 #define _ANONYMOUS_STRUCT
 #endif