Upstream commit "warnings be gone."

Adapted from upstream commits 84333e0475bc911adc16417f4ca327c975cf6c36
and 442cc6dc48f8188e097617f7f804c314a9dacd0e.
Upstream commit "Turn off debug tags in stagefright modules."

Adapted from upstream commit 0e6858d6aea12fc585a8c7d217c1271878655081.
Upstream commit "Check for ARCH_ARM_HAVE_NEON flag only for ARM arch"

This patch prevents ARM neon code from being included
for Arm64, where ARM is the 2nd architecture.

Adapted from upstream commit db46c2f8ff4b305a217adbbd406a61d10ae71db7.
Upstream commit "Fix PIC relocations for non-Bsymbolic builds"

The ARM assembly contains a couple of hand-coded PC relative references
to data defined in other object files. Make sure the externs are tagged
as hidden so the linker knows that it can resolve the reference locally
at build time.

Adapted from upstream commit 97e3e847179c17eb9059fb322413b6facd3e5a03.
Upstream commit "Add -no-integrated-as at local level."

Adapted from upstream commit 7cff5732dd9876ee9aabf08147e7efe3503637ff.