This change adds a new arch named "armv8-a-branchprot". The new target
is no different from the usual "armv8-a" variant except it has the
compiler flag "-mbranch-protection=standard" set.
With this flag compiler emits Armv8.3-A Pointer Authentication and
Armv8.5-A Branch Target Identification instructions. All of these
instructions are in the hint space; therefore devices which do not
support any of these extensions would execute them as NOPs.
In terms of directory structure there is no change in the output of
build/soong/scripts/build-ndk-prebuilts.sh script.
Test: build NDK prebuilts
Change-Id: Ie52ccba5653fbf567f0b7ca312d8a8e71602ad06
Make sure every exported function or type has a godoc comment.
Also makes minor changes like unexporting functions that are not used
outside the package and fixing minor style warnings.
Bug: 173449605
Test: m checkbuild
Change-Id: I533a595d02035aae8b2b603590be639826d2d4c8
