Fix bootstrapping with recent bits.

Fix bootstrapping with recent bits.

I can no longer bootstrap this package on my systems for a few reasons:

- Libtool has changed how nonrecursive libltdl is integrated
- The version of Gnulib in use does not bootstrap with dash
- The dxcommon scripts use Perl modules that I no longer install.

Do the necessary dance to fix all those issues, and resolve all the
resulting fallout.