[CI] Build zstd for release build container

[KornevNikita]

We enabled using zstd for release builds, but it requires zstd static library. zstd and libzstd-devel packages don't contain libzstd.a (note: it's rocky linux 8.10 / RHEL 8.10), therefore building from source.
Container build: https://github.com/intel/llvm/actions/runs/18755423984
SYCL release nightly: https://github.com/intel/llvm/actions/runs/18755907952

[uditagarwal97]

I have a script to build zstd from source in Ubuntu 24: https://github.com/intel/llvm/blob/sycl/devops/scripts/build_zstd_1_5_6_ub24.sh

Instead of adding steps to build zstd in dockerfile, maybe we can augment this script to work on RHEL as well and then use it for building release container? I don't have strong opinion on this approach, so I'm fine either way.

We use this script for building Ubuntu 24 docker image as well: https://github.com/intel/llvm/blob/sycl/devops/containers/ubuntu2404_base.Dockerfile#L20

[KornevNikita]

I have a script to build zstd from source in Ubuntu 24: https://github.com/intel/llvm/blob/sycl/devops/scripts/build_zstd_1_5_6_ub24.sh

Instead of adding steps to build zstd in dockerfile, maybe we can augment this script to work on RHEL as well and then use it for building release container? I don't have strong opinion on this approach, so I'm fine either way.

That's a good idea, but for now I'd prefer to proceed with the suggested approach to unblock the release nightly. Then I'll create a follow-up patch to use this script instead.

[KornevNikita]

Current container was built with this DockerFile - 94be7b8, so the release nightly is unblocked and we can proceed with using script without follow-up patch.

@uditagarwal97 I also updated the version of zstd since there is a new one and renamed the script, we are not tied to the 1.5.6. version, right?

[uditagarwal97]

@uditagarwal97 I also updated the version of zstd since there is a new one and renamed the script, we are not tied to the 1.5.6. version, right?

That's correct, as long as zstd releases are backward compatible, we can use the latest ones.

[uditagarwal97]

Can we also update the documentation: https://github.com/intel/llvm/blob/sycl/sycl/doc/GetStartedGuide.md#build-dpc-toolchain-with-device-image-compression-support

Note that the libzstd-dev package provided on Ubuntu 24.04 has a bug (link) and the zstd static library is not built with the -fPIC flag. Linking to this library will result in a build failure. For example: #15935. As an alternative, zstd can be built from source either manually or by using the build_zstd_1_5_6_ub24.sh script.

With the file being renamed, the link has to be updated. And maybe we can add a statement like this for RHEL as well.