crypto/boring: build constraints exclude all Go files

[dbenoit17]

The following program:

package main
import (
    "fmt"
    "crypto/boring"
)

func main() {
    fmt.Println("boring enabled:", boring.Enabled())
}

Produces the error

imports crypto/boring: build constraints exclude all Go files in /usr/lib/golang/src/crypto/boring

This is due to the public API missing the build tag change to !no_openssl. However, the curious thing is that running with -tags="boringcrypto" does not resolve the issue. @derekparker any thoughts?

[derekparker]

We can work around this by prefixing GOEXPERIMENT=boringcrypto to the go build command.