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• GCC is no longer supported. It will not be removed from the NDK just yet, but is no longer receiving backports. It cannot be removed until after libc++ has become stable enough to be the default, as some parts of gnustl are still incompatible with Clang. It will likely be removed after that point.
• Added simpleperf, a CPU profiler for Android: https://android.googlesource.com/platform/system/extras/+/master/simpleperf/README.md

• Additional fixes for missing __cxa_bad_cast: https://android-review.googlesource.com/q/topic:cxa_bad_cast-ndk-r13-release

• NDK_TOOLCHAIN_VERSION now defaults to Clang.
• libc++ has been updated to r263688.
  • We've reset to a (nearly) clean upstream. This should remove a number of bugs, but we still need to clean up libandroid_support before we will recommend it as the default.
• make-standalone-toolchain.sh is now simply a wrapper around the Python version of the tool. There are a few behavioral differences. See https://android-review.googlesource.com/#/c/245453/
• Some libraries for unsupported ABIs have been removed (mips64r2, mips32r6, mips32r2, and x32). There might still be some stragglers.
• Issues with crtbegin_static.o that resulted in missing atexit at link time when building a static executable for ARM android-21+ have been resolved: https://github.com/android-ndk/ndk/issues/132
• Added CMake toolchain file in build/cmake/android.toolchain.cmake.

• This is not intended to be a comprehensive list of all outstanding bugs.
• Standlone toolchains using libc++ and GCC do not work. This seems to be a bug in GCC. See the following commit message for more details: https://android-review.googlesource.com/#/c/247498
• x86 ASAN still doesn't work. See discussion on https://android-review.googlesource.com/#/c/186276/
• Bionic headers and libraries for Marshmallow and N are not yet exposed despite the presence of android-24. Those platforms are still the Lollipop headers and libraries (not a regression from r11).
• RenderScript tools are not present (not a regression from r11): https://github.com/android-ndk/ndk/issues/7.