diff --git a/ChangeLog b/ChangeLog
index bb190688bc..1074d9345a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Mar 19 02:13:00 2013  Kenta Murata  <mrkn@mrkn.jp>
+
+	* configure.in: set ac_cv_prog_cxx if CXX is supplied.
+
 Tue Mar 19 01:18:00 2013  Kenta Murata  <mrkn@mrkn.jp>
 
 	* configure.in: Fix c++ compiler auto-selection not only for
diff --git a/configure.in b/configure.in
index ee5e8b1cff..06af58e8b5 100644
--- a/configure.in
+++ b/configure.in
@@ -216,6 +216,7 @@ AS_CASE(["$build_os"],
       [xclang|x/usr/bin/clang],     [: ${CXX=clang++}])
   ])
 test -z "$CC" || ac_cv_prog_CC="$CC"
+test -z "$CXX" || ac_cv_prog_CXX="$CXX"
 
 if test "$program_prefix" = NONE; then
   program_prefix=