add RISCV clang for JSON dump

[axel-h]

I have missed this. Where is this used?

[lsf37]

It's used for generating the "HW Run" build matrix, and it currently indeed only has HIFIVE, gcc, but not HIFIVE, clang in it

[axel-h]

It's used for generating the "HW Run" build matrix, and it currently indeed only has HIFIVE, gcc, but not HIFIVE, clang in it

But where does this happen?

[lsf37]

It's called in the seL4 repo, e.g. in sel4test-hw.yml in

  the_matrix:
    name: Matrix
    needs: hw-build
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.matrix.outputs.matrix }}
    steps:
    - id: matrix
      uses: seL4/ci-actions/sel4test-hw-matrix@master

and then used later in

    strategy:
      fail-fast: false
      matrix: ${{ fromJson(needs.the_matrix.outputs.matrix) }}