Add docs on using Bionic with NativeAOT

Resolves dotnet#87340.

src/coreclr/nativeaot/docs/README.md

@@ -7,3 +7,4 @@
 - [Reflection In AOT](reflection-in-aot-mode.md)
 - [Troubleshooting](troubleshooting.md)
 - [RD.xml Documentation](rd-xml-format.md)
+- [Using Native AOT on Android-Bionic](android-bionic.md)

src/coreclr/nativeaot/docs/android-bionic.md

@@ -0,0 +1,26 @@
+# Using Native AOT with Android Bionic
+
+Starting with .NET 8 Preview 7, it's possible to build shared libraries and command line executables for Android.
+
+Not a full Android experience is available - it's only possible to publish for two Bionic RID: bionic-arm64 and bionic-x64. Publishing for Android RIDs (android-arm64/android-x64) is not possible. This limited experience corresponds to building with [Android NDK](https://developer.android.com/ndk) from Native code - the limitations are similar. Interop with Java needs to be done manually through JNI, if necessary.
+
+To build for Bionic:
+
+* Ensure you have [Android NDK](https://developer.android.com/ndk/downloads) for your system downloaded and extracted somewhere.
+* Update your PATH to include `{NDK_ROOT}\toolchains\llvm\prebuilt\{OS_ARCH}\bin`. Replace `{NDK_ROOT}` with the path where you extracted the NDK, and replace `{OS_ARCH}` with your host OS and architecture (e.g. windows-x86_64 or linux-x86_64). Make sure this entry is first in your path - we need to make sure that running `clang` will execute `clang` from this directory.
+* You can either create a new project or use an existing project. For this guide, let's create a new one:
+  ``sh
+  $ dotnet new console -o HelloBionic --aot
+  $ cd HelloBionic
+  ``
+  Note: the `--aot` parameter added `<PublishAot>true</PublishAot>` to the new project.
+* Publish the project:
+  ``sh
+  $ dotnet publish -r linux-bionic-arm64 -p:DisableUnsupportedError=true -p:PublishAotUsingRuntimePack=true
+  ``
+* You should have a binary under `bin\Release\net8.0\linux-bionic-arm64\publish`. Copy this to an Android device. Either `adb push` or using some GUI.
+* You can probably run it with `adb shell`, but I used Termux: open Termux, give it access to file system by running `termux-setup-storage`. This will give you access to phone storage under `~/storage`. Copy the binary from `~/storage/...` to `~` (internal storage is not executable and you won't be able to run stuff from it). Then `chmod +x HelloBionic` and `./HelloBionic`. You should see Hello World.
+
+Command line apps are not very interesting for Android. The more interesting scenario are shared libraries that can be called into from Java/Kotlin through JNI. This is very similar to building shared libraries in other languages like C/C++/Rust. `PublishAot` allows building shared libraries that are callable from non-.NET languages. See https://learn.microsoft.com/dotnet/core/deploying/native-aot/interop#native-exports.
+
+For an example of a Native AOT shared library invoked through JNI from Java see https://github.com/josephmoresena/NativeAOT-AndroidHelloJniLib.