diff --git a/ChangeLog b/ChangeLog
index 38051c0eba..92f438c245 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-08-20  Joseph Myers  <joseph@codesourcery.com>
+
+	* Makeconfig [$(enable-werror) = yes] (+gccwarn): Do not add
+	-Wno-error=undef.
+
 2015-08-20  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* i386/i686/multiarch/strcasestr-c.c: Removed.
diff --git a/Makeconfig b/Makeconfig
index f136b88da1..bbe83ec16a 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -750,7 +750,7 @@ else
 endif
 +gccwarn += -Wundef
 ifeq ($(enable-werror),yes)
-+gccwarn += -Werror -Wno-error=undef
++gccwarn += -Werror
 endif
 +gccwarn-c = -Wstrict-prototypes