This kind of thing is bound to get better as it gets wrapped in with a more idiomatic interface. Things like https://github.com/go-gl/gl started as ugly hacks requiring passing unsafe pointers and stuff around but have made great strides since then. I don't know the details and I'm thinking aloud right now, but the comments about "windows.h", constants, and accessing C via cgo possibly point to an automatically generated solution (possibly leveraging "go generate").

Whatever, native GUI bindings has been a key factor for the adoption (or lack thereof) of some languages where they would have otherwise been perfectly fine.