Allow Swift to be run on ubuntu runners

[rzuckerm]

It would be nice if the CodeQL action could be run on ubuntu runners. The macos runners are incredible slow. For this run it is taking 10 minutes just to build the Swift samples, and there are not that many.

[mbg]

Hi @rzuckerm,

The CodeQL Action works on Ubuntu/Linux, macOS, and Windows runners.

However, CodeQL itself only supports analysing Swift on macOS.

The team that looks after Swift support for CodeQL is aware that analyses can be slow, as well as the underlying reasons, and is investigating options for speeding things up.

[pascalecu]

So how come https://techtoaster.io/codeql-swift-code-scanning-on-linux-x86_64/ was able to make it work on Linux? what are the specific things that force CodeQL to work on macOS, considering Swift on Linux has been here for quite a while?

[coadaflorin]

While we never officially supported scanning Swift on Linux, the ability to scan Swift on Linux did exist in CodeQL. The intent behind supporting Swift was to extend security testing to mobile applications for iOs. As CodeQL required a working build in order to scan an iOs application, and macOS is the go to for most iOs developers, we decided to officially support scanning Swift code only on macOS.