Add (or make visible in docs) build tags for conditional compilation for target

[andrewfstratton]

When a module needs to be different for different devices - e.g. badger2040 and pybadge (where the displays have different devices, etc.) it would be great to allow for something like Go's ability to have one of:

1. filename identification for a target to allow only the relevant module to be built for a target device. e.g. something like the go os/architecture module name - but this would probably need to be - package_os_arch_target.go.
2. build tags in the module - though deciding on which style to use might be an issue and also some technical debt (since I think tinygo is not yet up to go:build version yet)

I imagine that filename based is quicker, easier and incurs less technical debt (at present) and should be sufficient for now.

[aykevl]

For this we use build tags. You can see the list of build tags using the tinygo info subcommand. For example:

~$ tinygo info badger2040
LLVM triple:       thumbv6m-unknown-unknown-eabi
GOOS:              linux
GOARCH:            arm
build tags:        cortexm baremetal linux arm rp2040 rp badger2040 tinygo math_big_pure_go gc.conservative scheduler.tasks serial.usb
garbage collector: conservative
scheduler:         tasks
cached GOROOT:     /home/ayke/.cache/tinygo/goroot-3a440b66d587e4e8eab2a8bcafe00a636ab2691224cdd9e8c1274c2ea5dc6fe9

build tags in the module - though deciding on which style to use might be an issue and also some technical debt (since I think tinygo is not yet up to go:build version yet)

TinyGo is Go, so this works just like you'd expect from regular Go. //go:build and // +build both work (although I'd recommend //go:build for new code). You can't exclude files using filename suffixes: that's not a supported feature in Go except for a number of special-cased build tags (like arm, linux, etc). There is not much TinyGo can do about this.

[andrewfstratton]

Excellent :)

(updated)

I have used //go:build badger2040 successfully.

I tried using filename suffix, as 'button_badger2040.go' - but this didn't work.

Could the docs be updated - maybe in the FAQ?