misc/cgo: re-enable some tests

The testso directory still needs to be enabled.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5731048
diff --git a/misc/cgo/stdio/hello.go b/misc/cgo/stdio/hello.go
index 58fc6d5..4ab3c74 100644
--- a/misc/cgo/stdio/hello.go
+++ b/misc/cgo/stdio/hello.go
@@ -2,9 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build ignore
+
 package main
 
-import "stdio"
+import "../stdio"
 
 func main() {
 	stdio.Stdout.WriteString(stdio.Greeting + "\n")