Bug: common_string.go:66:6: __xgo_orig__ redeclared in this block

[xhd2015]

When setting up mocks for functions with name _, xgo fails with this message.

The function is from GOROOT/src/crypto/tls/common_string.go:

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[CurveP256-23]
	_ = x[CurveP384-24]
	_ = x[CurveP521-25]
	_ = x[X25519-29]
}

It seems that func name _ is a special placeholder, which can never be called. So it is reasonable to skip trapping these functions.