Check that NDK-built modules only link to NDK-built modules

Modules built against the NDK should only link against modules also
built against the NDK (or link to the NDK prebuilts). This patch
attempts to catch these cases, and prints a large warning when this is
violated. Once the tree is cleaned up, this will change to an error.

Change-Id: Ib6ffcc38d9161abdbe45a58af26ba429fb6f1876