diff --git a/configure.ac b/configure.ac
index 8c23a50..0245458 100644
--- a/configure.ac
+++ b/configure.ac
@@ -14,6 +14,7 @@
 # Checks for programs.
 AC_PROG_CPP
 AC_PROG_CC
+AC_PROG_CXX
 AC_PROG_INSTALL
 AC_PROG_LIBTOOL
 AC_PROG_LN_S