State of cross-compilation support (eg: from mac OS to android)

It would be nice to update the Android.md on swift documentation to reflect the fact that building from linux isn't compulsory and provide steps on how to build for android from a mac.

I don't use macOS, so can't be me (I may be the only person using Swift who's never used it on an Apple platform, as I own no Apple hardware, not even an iPhone).

the work you've linked from @KittyMac seems to be about using a docker container based on an ubuntu distribution to actually build swift code targetting android.

Yes, many people find using such prebuilt Docker containers the easiest way to use a new toolchain, and of course Docker works fine on macOS, though he reports his work doesn't run on Apple Silicon, so you need macOS x86_64.

Does this mean one can't compile swift code to target android directly from a macos, without any kind of linux installation ?

Of course not, @v.gorlov maintained a mac->droid toolchain for several years, before recently discontinuing it.

in golang, one only needs to set a couple of environment variables (cpu architecture, operating system) before calling "go build" (on any platform), and the resulting library / executable will be directly working on the target system. Without having to install any kind of docker container, or VM or anything

golang's corporate sponsor, google, is highly multi-platform and the language is more aimed at such cross-platform use, unlike Swift's corporate sponsor. That said, what you want is available in these community-provided projects, though it requires more configuration.

Are there any equivalent in swift for targeting the android platform ?

I recently saw this company that is working on something like that, another one posted in the forum before. As my first Docker link shows, bridging Swift and Kotlin/JVM requires some work, so only these companies go to that extent: no OSS project does all that for free.