Fix up overlays for MacOS builds

When we build on MacOS since we create a sparseimage file to do
builds the location of the sdk overlays isn't correct.  Fix this
by copying the overlays/ dir into the mounted sparseimage file.

Signed-off-by: Kumar Gala <[email protected]>

Author: galak

go.sh

@@ -38,6 +38,7 @@ if [ "$machine" == "Mac" ]; then
 		hdiutil mount ${ImageNameExt}
 	fi
 	cp -a patches /Volumes/$ImageName
+	cp -a overlays /Volumes/$ImageName
 	cd /Volumes/$ImageName
 fi