Silly mistake (how on earth did it live this long?): adding -DNDEBUG

to CXXFLAGS should use $CXXFLAGS, not $CFLAGS.

This commit was SVN r5787.

config/ompi_configure_options.m4

@@ -135,7 +135,7 @@ fi
 #################### Early development override ####################
 if test "$WANT_DEBUG" = "0"; then
     CFLAGS="-DNDEBUG $CFLAGS"
-    CXXFLAGS="-DNDEBUG $CFLAGS"
+    CXXFLAGS="-DNDEBUG $CXXFLAGS"
 fi
 AC_DEFINE_UNQUOTED(OMPI_ENABLE_DEBUG, $WANT_DEBUG,
     [Whether we want developer-level debugging code or not])