add support for ARM based platforms

[muellerc]

*Description of changes:
The current version 2.0.0 doesn't support ARM based platforms, as the native code is compiled for x86 only.
This change extends the build process to [cross-] compile the native code for x86 and ARM. When executed on the target platform, it detects the underlying architecture (x86 or ARM) and loads these native libraries only.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[muellerc]

This change can be tested using this sample project: https://github.com/muellerc/lambda-java-ric-platform-test

[carlzogh]

Thanks again for the contribution - I've made a few changes on top of those in I've pushed a commit that does this: carlzogh@0b16ecd

@muellerc what do you think about including these changes in your PR? (I tried pushing to your fork but it seems I don't have permissions to do so)

[muellerc]

@carlzogh , I already managed to incorporate the proposed improvements. Let me know if there is something else I can do.

[msailes]

I tried looking at why this build was failing, but I can't work it out.

I can only think it's something to do with the phase in which lombok code is generated.

aws-lambda-java-libs/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/S3BatchResponse.java

Line 60 in bd490cb

public static S3BatchResponseBuilder fromS3BatchEvent(S3BatchEvent s3BatchEvent) {

I can't see what else it would be.

[msailes]

I took @muellerc branch changed the project version number. Ran make build in the aws-lambda-java-runtime-interface-client directory to install the proposed changes into my local repo.

Then I used this artefact to build a Lambda function which was then deployed to the ARM architecture on AWS Lambda.

Whereas previously this would cause an exception, I'm now getting a successful response.

edit - I should say this was all done my my Apple M1 laptop.

[carlzogh]

Thanks @msailes!

[carlzogh]

I've just released version 2.1.0 containing these changes - it should propagate to Maven Central and be available within a few hours. Thanks again @muellerc for your contribution and @msailes for your support!

[davidmelia]

@carlzogh - have you seen #316 - I think something has gone wrong with the JAR build as the ARM shared objects are actually x86

arm64/aws-lambda-runtime-interface-client.glibc.so: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, BuildID[sha1]=2b546f8d337d95e96fbf08f486a92ca29cde36da, not stripped
arm64/aws-lambda-runtime-interface-client.musl.so:  ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, with debug_info, not stripped

This means we cannot easily run on Apple M1 (have to use x86 docker platform param --platform=linux/amd64)