It would be good if someone were able to track down the causes of these
problems, so that parallel builds worked properly.
+=head2 Refactor C<xsubpp> to be a thin wrapper around C<ExtUtils::ParseXS>
+
+C<ExtUtils::ParseXS> encapsulates a version of the C<xsubpp> into a module.
+In effect this is a code fork, and it's likely that C<xsubpp> has had some
+bug fixes since the code from C<ExtUtils::ParseXS> was derived. It would be
+good to merge the differences in, reduce down to 1 canonical implementation,
+and convert C<xsubpp> to a very thin command line wrapper to
+C<ExtUtils::ParseXS>.
+
+In theory this needs no real C knowledge, as one way of approaching this task
+is to ensure that C<ExtUtils::ParseXS> generates identical output to C<xsubpp>
+for input XS files, which does not require understanding the contents of the
+output C file. However, some C knowledge is likely to help with testing, and
+locating/producing comprehensive test cases.
+
+
+
=head1 Tasks that need a little C knowledge