Go's main toolchain supports 38 different OS/arch pairs (`go tool dist list`), not including gccgo.
Three of those 38 are:
And those three are currently in need of love.
We've had problems with both hangs during builds as well as kernel crashes, so we've had to stop running our NetBSD builders during the last dev cycle, as sadly added to our upcoming Go 1.9 release notes:
If any NetBSD developers have time and/or interest, these bugs need attention:
Most concerning is our builders kernel panicing:
Until that's fixed, it's hard to make forward progress on other issues.