diff --git a/ChangeLog b/ChangeLog
index e228cfefca..e6cf05cdac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Thu Apr 21 12:14:04 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in: check if succeeded in creating config.h.
+
+	* tool/ifchange: ignore failures when TEST_COLORS unmatched. just
+	  use the default value if expected name is not contained in it.
+	  [ruby-core:75046] [Bug #12303]
+
 Wed Apr 20 17:33:31 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/cgi/escape/escape.c (cgiesc_unescape): define unescape
diff --git a/configure.in b/configure.in
index 10e1d0f0fc..508e6bb20b 100644
--- a/configure.in
+++ b/configure.in
@@ -4461,7 +4461,7 @@ guard=INCLUDE_RUBY_CONFIG_H
 (
   if test "x$CONFIGURE_TTY" = xyes; then color=--color; else color=; fi
   exec ${srcdir}/tool/ifchange $color "${config_h}" -
-)
+) || AC_MSG_ERROR([faild to create ${config_h}])
 tr -d '\015' < largefile.h > confdefs.h
 rm largefile.h
 
diff --git a/tool/ifchange b/tool/ifchange
index 7779b28a63..08aaba570c 100755
--- a/tool/ifchange
+++ b/tool/ifchange
@@ -40,7 +40,7 @@ target="$1"
 temp="$2"
 if [ "$temp" = - ]; then
     temp="tmpdata$$.tmp~"
-    cat > "$temp" || exit $?
+    cat > "$temp"
     trap 'rm -f "$temp"' 0
 fi
 
@@ -50,8 +50,8 @@ if [ "$color" = always -o \( "$color" = auto -a -t 1 \) ]; then
     case "`tput smso 2>/dev/null`" in
 	"$msg_begin"*m)
 	    if [ ${TEST_COLORS:+set} ]; then
-		msg_unchanged=`expr ":$TEST_COLORS:" : ".*:pass=\([^:]*\):"`
-		msg_updated=`expr ":$TEST_COLORS:" : ".*:fail=\([^:]*\):"`
+		msg_unchanged=`expr ":$TEST_COLORS:" : ".*:pass=\([^:]*\):"` || :
+		msg_updated=`expr ":$TEST_COLORS:" : ".*:fail=\([^:]*\):"` || :
 	    fi
 	    msg_unchanged="${msg_begin}${msg_unchanged:-32;1}m"
 	    msg_updated="${msg_begin}${msg_updated:-31;1}m"