Start distributing checkedc-clang compiler binaries again

[dtarditi]

It's complicated and hard to build your own clang compiler binaries. We need to start distributing pre-built compiler binaries again.

I discussed this with the Secure Software Development Project Board and we decided our target would be Linux Ubuntu (whatever the latest stable release is) and MacOS.

For Linux, we will not attempt to distribute it via package managers. We'll just provide people a prebuilt tarball. We don't have the time and resources to go through the packaging and distribution processes for all the difference flavors of Linux. For example, here it e guide for Ubuntu (and that's just one flavor of Linux). We'd also have to make sure that any install of the Checked C clang doesn't conflict with a default system install of clang. While checkedc-clang already has a different name than clang.exe, we haven't looked into all the other binaries built with clang.

We might optionally distribute binaries for Windows. Windows OS code signing requirements are expensive, confusing, and onerous for open-source projects (see this article on what the developer of Notepad++ ran into. Certum may provide a reasonable solution.

[dtarditi]

This is completed. We've released binaries for Mac, Ubuntu Linux, and Windows.