dockerfile: enable SIMD optimization for x86_64, amd64, arm64 and aarch64

[edsiper]

---

Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[edsiper]

FYI: we will put this PR on hold until next minor release.

[patrick-stephens]

This won't work for containers on emulated targets - it takes the value from the host. If you try to build the container on a different host then it'll just take whatever value the host is.
Personally I think we should make this backwards compatible and just pass it in as required. People can then adopt it as required and configure it appropriately for their host. I know this attempts to discover it if not set but it will be auto-applied for those who may not want it.

[patrick-stephens]

I think we will have to update container builds to be split per target to support this as well (i.e. build and push by digest for a specific arch/target and then make a multi-arch/target manifest separately), rather than the simple current approach we have of building all on the same target:

fluent-bit/.github/workflows/call-build-images.yaml

Lines 115 to 131 in 58cc2d5

	- name: Build the production images
	id: build_push
	uses: docker/build-push-action@v6
	with:
	file: ./dockerfiles/Dockerfile
	context: .
	tags: ${{ steps.meta.outputs.tags }}
	labels: ${{ steps.meta.outputs.labels }}
	platforms: linux/amd64, linux/arm64, linux/arm/v7, linux/s390x
	target: production
	# Must be disabled to provide legacy format images from the registry
	provenance: false
	push: true
	load: false
	build-args: |
	FLB_NIGHTLY_BUILD=${{ inputs.unstable }}
	RELEASE_VERSION=${{ inputs.version }}

Currently the image you make with this change would just be based on the host.

This was requested anyway to support other things like a common image for both Linux and Windows: #9509