Investigate the inclusion of PRs to the previous repo

[win93]

• Ignore LZMA_BUF_ERROR Quintus/ruby-xz#18
• Adding spec file Quintus/ruby-xz#5

Placing these links here for tracking purposes because these are two PRs worth looking into pulling in. This also gives a place for the contributors to add comments regarding the pull requests until I can figure out how to go about including these PRs into the repo.

If you are the requester of either of these PRs, it would probably be easiest if you re-did your pull request against this repo. (If you take no action, I can still pull your code once I've looked through your PR, so this action is not required.)