Ignore UA build products.
OS detection doesn't print out spurious messages when not on Linux
Mac UA build fixes

* Restore dynamic linking on mac builds
* The openssl build on mac needs the same treatment as other
  builds (install into openssl/stage rather than a system directory).
* The Mac build in particular doesn't seem to like relative paths, so
  supply an absolute one.

Bumps UA version to 1.4.9.