Further GCC flags, options, etc.

Change-Id: I6c73da16d2dc5f1540bffd6a098490f0ef8bcdc0
Use Generic Paths for GCC Version
Clang Flags and Options

Change-Id: Ief5a9b4f8513b34d2a365068d62f6116ac439160
build: no longer build emulator by default

This is just increasing build times when most people are not using it.
Let's speed up builds a bit.

Building emulator should still be possible by appending BUILD_EMULATOR=true
to the build command

Change-Id: Ibd8e2b90455bd603a691c7b95466068b6fae212a
Fix Clang Build

Change-Id: I67c087591c4aab4644c606bedc03d6483c54e269
Set HAVE_UNWIND_CONTEXT_STRUCT for Clang

Change-Id: I423d650181c6736111e4a5e91ded81c471dd08e1
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
Further LTO fixes

Change-Id: I233159e441430b926b655d8bb2e8c084343bd153