The `go build -gcflags -S internal/utils/str.go 2> test.s` worked i.e. the stdout was empty and the stderr needs to be redirected `2> test.s`. 
Use the `mcedit test.s` to see asm. 

I'll try the https://github.com/loov/lensm
````sh
go install --tags nox11 loov.dev/lensm@main
sudo apt install libwayland-dev libvulkan-dev libegl-dev libxkbcommon-dev libxfixes-dev
go install --tags nox11 loov.dev/lensm@main
lensm -watch -filter Fibonacci lensm
```