Document the NDK's built-in toolchain file.
The third-party toolchain file doesn't actually work with newer NDKs,
and the one shipped with the NDK has fewer bugs.
Change-Id: I59e1db393f0d66b186fb71590fab14db7faa0756
Reviewed-on: https://boringssl-review.googlesource.com/24165
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/BUILDING.md b/BUILDING.md
index 97de4c3..46f27e3 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -79,14 +79,15 @@
### Building for Android
-It's possible to build BoringSSL with the Android NDK using CMake. This has
-been tested with version 10d of the NDK.
+It's possible to build BoringSSL with the Android NDK using CMake. Recent
+versions of the NDK include a CMake toolchain file which works with CMake 3.6.0
+or later. This has been tested with version r16b of the NDK.
Unpack the Android NDK somewhere and export `ANDROID_NDK` to point to the
directory. Then make a build directory as above and run CMake like this:
cmake -DANDROID_ABI=armeabi-v7a \
- -DCMAKE_TOOLCHAIN_FILE=../third_party/android-cmake/android.toolchain.cmake \
+ -DCMAKE_TOOLCHAIN_FILE=${ANDROID_NDK}/build/cmake/android.toolchain.cmake \
-DANDROID_NATIVE_API_LEVEL=16 \
-GNinja ..
@@ -94,7 +95,11 @@
can replace `armeabi-v7a` in the above with `arm64-v8a` and use API level 21 or
higher to build aarch64 binaries.
-For other options, see [android-cmake's documentation](./third_party/android-cmake/README.md).
+For older NDK versions, BoringSSL ships a third-party CMake toolchain file. Use
+`../third_party/android-cmake/android.toolchain.cmake` for
+`CMAKE_TOOLCHAIN_FILE` instead.
+
+For other options, see the documentation in the toolchain file.
### Building for iOS
