x/mobile: Cannot cross compile for darwin.

[seriousnerve]

What version of Go are you using (go version)?

1.10.2

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Windows 10, x86_x64

What did you do?

I tried to build package gl from mobile by running go install golang.org/x/mobile/gl/

If possible, provide a recipe for reproducing the error.

Just set GOOS=darwin and run go install golang.org/x/mobile/gl/

What did you expect to see?

I expected the command to complete successfully!

What did you see instead?

I saw it error with this:

(#) golang.org/x/mobile/gl
..\go\src\golang.org\x\mobile\gl\gl.go:20:12: undefined: context

[odeke-em]

/cc @eliasnaur @rakyll @crawshaw

[eliasnaur]

Cross compiling the gl package is unlikely to work, since it requires Cgo and the native OpenGL headers to compile. If you pass CGO_ENABLED=1 along with GOOS=darwin to go install you'll probably run into a missing C header file or similar.