[acpica] Set alignment on acpi_table_facs to appease Clang

The acpi_table_facs, like many other ACPI structs, uses byte-packing to
match ACPI specification, but that means Clang insists on generating a
call to __atomic_compare_exchange_n intrisic to satistfy alignment
requirements when trying to atomically set the value for GlobalLock.
This is undesirable, especially since acpi_table_facs does not need
one byte alignment. So to appease Clang, we explicitly set the 4 byte
alignment for this struct, and enable -Wpadded error for this struct to
ensure we catch any potential future regressions.

Change-Id: I638bd500ba01d5a6f38ccd598e66a6ba65460e84

[public][ulib][dev] Add __FALLTHROUGH macro for warning suppression

GCC 7 enables -Wimplicit-fallthrough with -Wextra, so we'll get it.
Clang has it available, so start using it and clean up code accordingly.

The GCC feature will actually recognize some formulaic comments to
suppress the warning. But there's also an explicit syntax, and
C++17 added a standard one. So use that instead, via the new macro
__FALLTHROUGH in <zircon/compiler.h>.

TC-36 #comment Clean up code in preparation for more -Wimplicit-fallthrough

Change-Id: I28309c91c32db1313d52f4255836c5ea687e141f

[acpica] Export AcpiHwSetFirmwareWakingVector

This is the internal function used to implement AcpiSetFirmwareWakingVector,
the usual API for setting the wake-from-suspend address. That API makes
assumptions about how much of the ACPICA environment is setup that
aren't true for our kernelmode, so we expose the inner mechanism that
bypasses those assumptions.

ZX-1184

Change-Id: I8367fbaf9f51fc93446aa7c8e05b0947073ab887

[powerctl][acpi] Partially implement S-state transition

This implements enough of the S-state transition code to be used for the
shutdown codepath, and for suspending-to-RAM (but not resuming).

ZX-1184

Change-Id: I88aa959db1a77e903e1f98c8d5ea83a825ff24fe

[prebuilt] Update Clang toolchain

This change also fixes errors caused by -Wnull-pointer-arithmetic.

Change-Id: Id4ee4e1c6308a03508061a5a3ebe2817ee05b109

[kernel][acpica] Trim out some unused source files

Change-Id: I3a2f750ebea24de28149aa43c65695cde8ee1f7a

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[acpi] Use more conservative CFLAGS

ACPICA and the ACPI service were building with -Wno-strict-aliasing,
which silences warnings about strict aliasing violations. This takes
the more conservative approach of disabling strict-aliasing-based
optimizations.

Change-Id: I42c4a4d4fd121a20ee19437ae31779ee6a011297

[kernel][acpica] Convert osmagenta.c to C++

Change-Id: I58a0bf6eb1037199672ab36580ee0288a6191f41

[lib][acpica] Fix Clang warnings

The -Wno-incompatible-pointer-types-discards-qualifiers switch
silences a large number of warnings in this third-party library.
-Wno-format-signedness is understood by GCC but not by Clang, so
don't use it for Clang.

Change-Id: Ifbff3aa8abd560fcc89583170f7fff0a54fda2a3

[kernel][acpi] Fix build without linker gc

Needed to add and remove some components to get the no-linker-gc
build to be satisfied.

Change-Id: I7233080ea9d60d076971c5e4dc7d6b8d1496f248

[kernel] enable stricter printf warnings

Change-Id: I02347b0716cec4e3e147318d37415d194b0affe4

[build] Use boolean flags to enable Clang

This is to match other flags used by the build.

Change-Id: Idd1c1714aff3d03dbc58b92a2cbe0ee0a75d8089

[acpi] Reduce the amount of ACPICA built for the kernel

This also removes the suspend-to-RAM stub for x86, which broke
when we moved ACPI out of the kernel anyway.

Change-Id: Iece785ce429c11a00a1489340fc55d2e645b5b6f

[build] Rename GLOBAL_INCLUDES to KERNEL_INCLUDES as it only applies in kernel

The confusingly named GLOBAL_INCLUDES variable only applies to kernel
targets, not userspace targets. This renames the variable so we can
add a GLOBAL_INCLUDES that actually applies to both. This also moves
the exported variable to kernel-config.mk as it is kernel-internal.

Change-Id: I22edd603a9970d621b270e8dfbe7192676e65b47

[acpica] Contain ACPICA include path better

Previously acpica was cluttering the global include path. This
diff contains its includes into an acpica directory.

Change-Id: I75bba0ede99259cfb40366ab6170e5281304405f

[magenta] Initial commit