We have some standardized emoji like . Seems like the partial 2019 solution would be to use emoji that should work in any modern font (you could make a more UNIXy-feeling font if you want everything to look less skeuomorphic and more stripped-down). This doesn't cover every programming-specific use case, but it's a nice compromise I haven't seen mentioned here.
Indeed, there is a WG2/UTC proposal to officially add Powerline symbols to Unicode [1]. The problem of this approach is that those standards are very strongly (and probably rightly) governed with a lot of crufts and limitations, for example you can't put Github symbol there because it is trademarked.
the partial 2019 solution would be to use emoji that should work in any modern font
This usually works not by having fonts define emojis (most don't) - it's just that systems reach in and render emojis from a dedicated emoji-defining font when they encounter them. So it's not like the world is full of fonts that define 'standard emojis' or funky powerline symbols.
