Some of these requirements should be built into any build tool. However, most can be added easily enough:
For instance, redux [https://github.com/gyepisam/redux] is written in Go (not compiled for binary distribution, but I could add that), is cross platform, supports any mix of languages and tasks, is very easy to learn.
It uses shell scripts to create targets so everything is scriptable.
Stuff like recognizing standard folder hierarchies and auto-discovery can be added with small scripts or tools.
It can be as simple as you want or as complex as you need.
For instance, redux [https://github.com/gyepisam/redux] is written in Go (not compiled for binary distribution, but I could add that), is cross platform, supports any mix of languages and tasks, is very easy to learn.
It uses shell scripts to create targets so everything is scriptable. Stuff like recognizing standard folder hierarchies and auto-discovery can be added with small scripts or tools. It can be as simple as you want or as complex as you need.