Add solaris build support

Signed-off-by: Edward Pilatowicz <edward.pilatowicz@oracle.com>

fs/dtype_test.go

@@ -0,0 +1,26 @@
+package fs
+
+import (
+	"testing"
+
+	"github.com/containerd/containerd/testutil"
+)
+
+func TestRequiresRootNOP(t *testing.T) {
+
+	// This is a dummy test case that exist to call
+	// testutil.RequiresRoot() on non-linux platforms.  This is
+	// needed because the Makfile root-coverage tests target
+	// determines which packages contain root test by grepping for
+	// testutil.RequiresRoot.  Within the fs package, the only test
+	// that references this symbol is in dtype_linux_test.go, but
+	// that file is only built on linux.  Since the Makefile is not
+	// go build tag aware it sees this file and then tries to run
+	// the following command on all platforms: "go test ...
+	// github.com/containerd/containerd/fs -test.root".  On
+	// non-linux platforms this fails because there are no tests in
+	// the "fs" package that reference testutil.RequiresRoot.  To
+	// fix this problem we'll add a reference to this symbol below.
+
+	testutil.RequiresRoot(t)
+}