Context: https://github.com/android/ndk/wiki/Changelog-r23#changelog
The most important changes for Xamarin.Android:
NDK r23 removes GNU Binutils and so we need to switch to using our
bundled copy of them.
Upstream changes:
* Includes Android 12 APIs.
* Updated LLVM to clang-r416183b, based on LLVM 12 development.
* [Issue 1047]: Fixes crash when using ASan with the CFI unwinder.
* [Issue 1096]: Includes support for [Polly]. Enable by adding `-mllvm -polly`
to your cflags.
* [Issue 1230]: LLVM's libunwind is now used instead of libgcc for all
architectures rather than just 32-bit Arm.
* [Issue 1231]: LLVM's libclang_rt.builtins is now used instead of libgcc.
* [Issue 1406]: Fixes crash with Neon intrinsic.
* Vulkan validation layer source and binaries are no longer shipped in the NDK.
The latest are now posted directly to [GitHub](https://github.com/KhronosGroup/Vulkan-ValidationLayers/releases).
* Vulkan tools source is also removed, specifically vulkan_wrapper.
It should be downloaded upstream from [GitHub](https://github.com/KhronosGroup/Vulkan-Tools).
* The toolchain file (android.toolchain.cmake) is refactored to base on CMake's
integrated Android support. This new toolchain file will be enabled by default
for CMake 3.21 and newer. No user side change is expected. But if anything goes
wrong, please file a bug and set `ANDROID_USE_LEGACY_TOOLCHAIN_FILE=ON` to
restore the legacy behavior.
* When using the new behavior (when using CMake 3.21+ and not explicitly
selecting the legacy toolchain), **default build flags may change**. One
of the primary goals was to reduce the behavior differences between our
toolchain and CMake, and CMake's default flags do not always match the
legacy toolchain file. Most notably, if using `CMAKE_BUILD_TYPE=Release`,
your optimization type will likely be `-O3` instead of `-O2` or `-Oz`. See
[Issue 1536] for more information.
* [Issue 929]: `find_library` now prefers shared libraries from the sysroot over
static libraries.
* [Issue 1390]: ndk-build now warns when building a static executable with the
wrong API level.
* [Issue 1452]: `NDK_ANALYZE=1` now sets `APP_CLANG_TIDY=true` rather than using
scan-build. clang-tidy performs all the same checks by default, and scan-build
was no longer working. See the bug for more details, but no user-side changes
should be needed.
[Issue 929]: android/ndk#929
[Issue 1047]: android/ndk#1047
[Issue 1096]: android/ndk#1096
[Issue 1230]: android/ndk#1230
[Issue 1231]: android/ndk#1231
[Issue 1390]: android/ndk#1390
[Issue 1406]: android/ndk#1406
[Issue 1452]: android/ndk#1452
[Issue 1536]: android/ndk#1536
[Polly]: https://polly.llvm.org/