commit 70f477360fb0ecccc0038231e2d4577a51d88dcd
Author: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Date:   Mon Feb 11 14:14:41 2013 -0500

    * configure.in: added --disable-werror option.
      [Bug #7830] [ruby-core:52131]

diff --git a/ChangeLog b/ChangeLog
index 5ea6b4a..c5b56af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Feb 12 04:11:09 2013  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* configure.in: added --disable-werror option.
+	  [Bug #7830] [ruby-core:52131]
+
 Mon Feb 11 23:08:48 2013  Tanaka Akira  <akr@fsij.org>
 
 	* configure.in: enable rb_cv_page_size_log test for MirOS BSD.
diff --git a/configure.in b/configure.in
index 732dd5d..1a40528 100644
--- a/configure.in
+++ b/configure.in
@@ -615,9 +615,13 @@ AC_DEFUN(RUBY_TRY_LDFLAGS, [
     save_LDFLAGS=
 ])
 
+AC_ARG_ENABLE(werror,
+        AS_HELP_STRING([--disable-werror],
+        [don't make warnings into errors even if a compiler support -Werror feature.]),
+        [particular_werror_flags=$enableval], [particular_werror_flags=yes])
+
 rb_cv_warnflags="$warnflags"
 if test "$GCC:${warnflags+set}:no" = yes::no; then
-    particular_werror_flags=yes
     for wflag in -Wno-unused-parameter -Wno-parentheses -Wno-long-long \
 		 -Wno-missing-field-initializers \
 		 -Wunused-variable \
@@ -625,11 +629,9 @@ if test "$GCC:${warnflags+set}:no" = yes::no; then
 		 -Werror=write-strings \
 		 -Werror=declaration-after-statement \
 		 -Werror=shorten-64-to-32 \
-		 -Werror-implicit-function-declaration \
+		 -Werror=implicit-function-declaration \
 		 ; do
-	if test "$particular_werror_flags" = yes; then
-	    wflag=`echo x$wflag | sed 's/^x-Werror-/-Werror=/;s/^x//'`
-	else
+	if test "$particular_werror_flags" = no; then
 	    wflag=`echo x$wflag | sed 's/^x-Werror=/-W/;s/^x//'`
 	fi
 	ok=no