diff --git a/m4/cxx0x_constexpr.m4 b/m4/cxx0x_constexpr.m4
index c9fe9c5278b76e0b136b53ba90e9af971e40be66..77f8f35df3b4ed997c8dd92b73f480bb81c4cd2a 100644
--- a/m4/cxx0x_constexpr.m4
+++ b/m4/cxx0x_constexpr.m4
@@ -1,6 +1,5 @@
 AC_DEFUN([CONSTEXPR_CHECK],[
   AC_REQUIRE([AC_PROG_CXX])
-  AC_REQUIRE([GXX0X])
   AC_LANG_PUSH([C++])
   AC_MSG_CHECKING([whether constexpr is supported])
   AC_COMPILE_IFELSE(