Add signed integer overflow checking to zlib

Migrate zlib over to Clang in order to use -ftrap to abort on signed
overflow

Change-Id: Ib2feb1dca89e18b4621b2fee0004b0f4d96d3dce
Revert "Add signed integer overflow checking to zlib"

The build is broken.

This reverts commit 4018ebf35d1ab1cd6b1340f44df0a1095cb5d10d.