GitLab

Use automake+libtool instead of simplemake+createshlib.  Parallel make
now works for real, and shared library creation should be more robust on
more platforms.  "make dist" now works, modulo building the documentation,
although for boring reasons we can't actually use it for the final
distribution tarball generation.

This is a massive change and without a doubt has some bugs in it.  We'll
work through them as we find them.

No reviewer.