The dependency securemessage fails to build because of it's dependency gtest failing to build thus causing ukey to also, fail to build. I have created a PR for securemessage that brings its gtest submodule to the commit that fixes the issue. The PR causes securemessage to successfully build again, and thus causes ukey2 to also build successfully.
If the PR that fixes the securemessage issue is merged, the submodule in this repository will need to be updated to reflect that.