* Windows does not define __ARM_NEON
However, Windows requires NEON to work, so assume it is there if build with MSVC
* Clarify NEON availability in MSVC targeting arm64
* Fix Formatting
* Add FreeBSD Arm64 detection
Getting all the features is handled by reading /var/run/dmesg.boot. Feature detections were taken from the freebsd kernel code sys/arm64/arm64/identcpu.c
* Add FreeBSD Arm64 tests
* Add flagm, flagm2 and rng detection
* Add HWCAP FreeBSD AArch64
* Update include to use linux hwcaps for powerpc
* Add FreeBSD aarch64 impl
* Separate Hwacps to freebsd and linux implementation
* Add aarch64 midr_el1 implementation
* Add detection hwcap cpuid to hwcaps.h
* Add MIDR_EL1 tests
* Add Windows Arm64 support
To add Windows Arm64 support was added detection of features via Windows API function IsProcessorFeaturePresent. Added _M_ARM64 to detect CPU_FEATURES_AARCH64 macro on Windows. Added initial code for Windows Arm64 testing and provided test for Raspberry PI 4. We can't use "define_introspection_and_hwcaps.inl" as a common file for all operating systems due to msvc compiler error C2099: initializer is not a constant, so as a workaround for Windows I used separate "define_introspection.inl"
See also: #268, #284, #186
* [CMake] Add windows_utils.h to PROCESSOR_IS_AARCH64
* Add detection of armv8.1 atomic instructions
* Update note on win-arm64 implementation and move to cpuinfo_aarch64.h
* Remove redundant #ifdef CPU_FEATURES_OS_WINDOWS
* Add note on FP/SIMD and Cryptographic Extension for win-arm64
* Add comments to Aarch64Info fields
Added comments to specify that implementer, part and variant we set 0 for Windows, since Win API does not provide a way to get information. For revision added comment that we use GetNativeSystemInfo
* Add documentation for X86 OS support
* Update X86 documentation
* Remove outdated cache info comment
* Update x86 documentation according to comments
* Update Internal structures documentation
* add windows ssse3,sse4_1,sse4_2 detection for non avx path
* remove special WESTMERE case
* move windows conditional redefinition to separate header
* fix minor issues
This commit helps with platform code separation (fixes#3). It should also help with the build as we can simply include all `impl_*.c` files regardless of OS / arch.
Note: this patch contains breaking changes in `include/cpu_features_macros.h`
- `CPU_FEATURES_OS_LINUX_OR_ANDROID` does not exist anymore
- `CPU_FEATURES_OS_FREEBSD`, `CPU_FEATURES_OS_ANDROID` and `CPU_FEATURES_OS_LINUX` are now mutually exclusive (i.e. `CPU_FEATURES_OS_ANDROID` does not imply `CPU_FEATURES_OS_LINUX`)
- `CPU_FEATURES_OS_DARWIN` has been renamed into `CPU_FEATURES_OS_MACOS` to be able to target non-Mac Apple products (IOS, TV, WATCH). They are now targetable with `CPU_FEATURES_OS_IPHONE`. This matches Apple naming convention described in [this stackoverflow](https://stackoverflow.com/a/49560690).
