diff --git a/configure.in b/configure.in
index 39dc1d38..87dea07d 100644
--- a/configure.in
+++ b/configure.in
@@ -187,6 +187,7 @@ AC_ARG_ENABLE(nls,
   NLS="-DNLS"
 )
 AC_SUBST(NLS)
+CXXFLAGS="$CXXFLAGS $NLS"
 
 AC_CHECK_LIB(xpg4, setlocale, LIBS="$LIBS -lxpg4")