We're adding TPU support to the builder by creating a new tpu-ubi9 variant that builds vLLM with PyTorch XLA for Google Cloud TPUs.

This is a initial division of tasks. As the work progresses, some of these will be further subdivided. For example, sub-tasks in Task 1 and 2 wil defintely be subdiveded because they involve muliple steps. Also, new tasks and sub-tasks will be added as more work in identified.

Task 1: Container setup

Set up TPU build container with required development tools

Sub-tasks:

1. Install Clang compiler (JAX recommends Clang)
2. Install Bazel build system for JAX compilation
3. Install CMake, Ninja build system, and Python development headers etc

Task 2: Package build plugins

Create build plugins to compile TPU dependencies from source

Sub-tasks:

1. Extend PyTorch plugin to verify TPU builds
2. Create PyTorch XLA build plugin
3. Create JAX/jaxlib build plugin with Bazel support
4. Update vLLM plugin with TPU dependency

Task 3: Build configuration

Configure build arguments and package collections for TPU

Sub-tasks:

1. Create TPU build arguments file with compiler versions and source repos
2. Set up TPU package collection (collections/accelerated/tpu-ubi9/)
3. Add TPU-specific build environment to vLLM settings (overrides/settings/vllm.yaml)
4. Register TPU variant in build system i.e., chnages to  Makefile

Task 4: CI/CD pipeline

Add TPU variant to GitLab CI pipeline 

Sub-tasks:

1. Add TPU build and test jobs to main CI configuration
2. Update shared CI templates to include TPU variant
3. Test complete build pipeline with bootstrap script (./bin/bootstrap.sh)

Task 5: Testing, to be scoped