Add a global define for non-external code.

There are some code policies we want to enforce more strictly, but
it's hard to do so for third party code because we have to either
carry the diff burden or upstream the patch, and in the latter case
the turnaround time for fixes can be problematic, and sometimes
upstream won't accept changes (sometimes people just need to win the
obfuscated C contest).

We define ANDROID_STRICT for any code that we expect to be able to
make these policy fixes as we change policies.

Change-Id: I15faf62cec1932dd859a082f66942b2606d0ff45