Reland "[sdk] Remove private headers from SDK"

This is a reland of 37d8ac4810530285a8063e093f2ad37940e31a40

Original change's description:
> [sdk] Remove private headers from SDK
>
> Consumers of the SDK should not be using these headers. We're going to
> replace these ioctls with FIDL.
>
> Test: None.
> Change-Id: I43681db00ec40f70efea8cbc50f3bae3e25f84a1

Test: Chromium successfully builds against resulting SDK (see https://fuchsia-sdk-chromium-roll.skia.org/).
Change-Id: Ib20f928a36bb30e109e781191e4e1621f83f723f
diff --git a/sdk/foundation/makesdk.go b/sdk/foundation/makesdk.go
index d402a04..93ce287 100755
--- a/sdk/foundation/makesdk.go
+++ b/sdk/foundation/makesdk.go
@@ -77,9 +77,10 @@
 }
 
 var (
-	hostOs     string
-	hostCpu    string
-	components []component
+	hostOs      string
+	hostCpu     string
+	components  []component
+	privateDirs []string
 )
 
 func init() {
@@ -276,6 +277,12 @@
 	for _, f := range files {
 		components = append(components, component{f.flag, f.src, f.dst, fileType, nil})
 	}
+	privateDirs = []string{
+		"arch/arm64/sysroot/include/zircon/device",
+		"arch/x64/sysroot/include/zircon/device",
+		"sysroot/aarch64-fuchsia/include/zircon/device",
+		"sysroot/x86_64-fuchsia/include/zircon/device",
+	}
 }
 
 func createLayout(manifest, fuchsiaRoot, outDir string) {
@@ -509,6 +516,9 @@
 			}
 		}
 	}
+	for _, d := range privateDirs {
+		os.RemoveAll(filepath.Join(*outDir, d))
+	}
 	if *archive {
 		if err := createTar(*outDir, *output); err != nil {
 			log.Fatalf("failed to compress %s: %v", *outDir, err)