Instructions to Build an Android chat app result in a failed build.

[Nutkey]

Describe the issue
The steps to build an Android chat app fail when building the Android Archive because environment variable ANDROID_SDK is not set.

To Reproduce
Run through the steps in https://learn.arm.com/learning-paths/mobile-graphics-and-gaming/build-llama3-chat-android-app-using-executorch-and-xnnpack/

In Build and Run Android Chat App -> Build the Android Archive , the command

sh scripts/build_android_library.sh

fails with

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':executorch_android:extractDebugAnnotations'.
> SDK location not found. Define a valid SDK location with an ANDROID_HOME environment variable or by setting the sdk.dir path in your project's local properties file at '/Users/bblaukopf/Bananas/executorch/extension/android/local.properties'.

Expected behaviour
In Build and Run Android Chat App -> Build the Android Archive
The command sh scripts/build_android_library.sh should report success.

Workaround
First run
export ANDROID_SDK=$ANDROID_HOME and then run sh scripts/build_android_library.sh which will now succeed.

Note that scripts/build_android_library.sh references the ANDROID_SDK environment variable. This variable has been deprecated for so long that even its replacement (ANDROID_SDK_ROOT) has been deprecated.

It would therefore be preferable to fix the script.

Environment
macOS 15.7.1
MacBook Pro 16" 2021
Apple M1 Pro 32GB