diff --git a/ChangeLog b/ChangeLog
index 4052e53d85..bc33b12e4d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Dec 14 11:25:20 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* configure.in: Add -Werror=declaration-after-statement to default
+	  warning flag. If you are using GCC, this flag is useful to
+	  prevent breaking VC build.
+
 Tue Dec 14 10:25:57 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/openssl/ossl_asn1.c (ossl_asn1_decode0): how many gcc-c99isms
diff --git a/configure.in b/configure.in
index 26ab9749aa..9dacccd369 100644
--- a/configure.in
+++ b/configure.in
@@ -445,6 +445,7 @@ AC_DEFUN(RUBY_TRY_LDFLAGS, [
 
 if test "$GCC:${warnflags+set}:no" = yes::no; then
     for wflag in -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings \
+		 -Werror=declaration-after-statement \
 		 -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long; do
 	RUBY_TRY_CFLAGS($wflag, [warnflags="${warnflags+$warnflags }$wflag"])
     done