diff --git a/m4/Makefile.am b/m4/Makefile.am
index c012a103c50449d15afeac46bf96f9d55ef1351e..e779c580cd66002af598303579b464aad496c56d 100644
--- a/m4/Makefile.am
+++ b/m4/Makefile.am
@@ -19,6 +19,7 @@ ALLM4S = 					\
 	cxx0x_variadic_constructor_sfinae.m4    \
 	cxx11_initializer_list.m4		\
 	cxx11_conditional.m4			\
+	cxx11_constexpr.m4			\
 	dune.m4					\
 	dune_all.m4				\
 	dune_autobuild.m4			\