RM llvm-toolchain-12 from kinetic

[Simon Chopin]

This package blocks the glibc 2.36 transition due to breakage of libsanitizer that isn't observed on later versions of LLVM. Plus, it has already been removed from Debian testing due to this bug:

https://bugs.debian.org/1012193

❯ reverse-depends src:llvm-toolchain-12
Reverse-Recommends
* libmkl-dev [amd64] (for libomp-12-dev)
* libmkl-rt [amd64] (for libomp-12-dev)

Reverse-Depends
* libllvmspirvlib12 (for libllvm12)
* libopencl-clang12 (for libclang-cpp12)
* libopencl-clang12 (for libllvm12)
* libpocl2 [amd64 arm64 armhf]
* libpocl2 [amd64 arm64 armhf]
* libpocl2 [amd64 arm64 armhf]
* llvm-spirv-12 (for libllvm12)
* nvidia-cuda-toolkit [amd64 arm64 ppc64el]

❯ reverse-depends -a source src:llvm-toolchain-12
Reverse-Build-Depends
* opencl-clang-12 (for libclang-cpp12-dev)
* opencl-clang-12 (for libclang-12-dev)
* opencl-clang-12 (for llvm-12-dev)
* opencl-clang-12 (for clang-12)
* pocl (for clang-12)
* pocl (for libclang-cpp12-dev)
* pocl (for llvm-12-dev)
* pocl (for libclang-12-dev)
* spirv-llvm-translator-12 (for llvm-12-dev)
* spirv-llvm-translator-12 (for libclang-12-dev)
* thunderbird (for llvm-12-dev)
* thunderbird (for libclang-12-dev)
* thunderbird (for clang-12)

In the case of libmkl-* and thunderbird, the dependencies are in OR clauses with later versions of LLVM, so there shouldn't be any breakage.

pocl is fixed in -proposed, and is waiting on AA resolution of https://bugs.launchpad.net/ubuntu/+source/pocl/+bug/1987621

nvidia-cuda-toolkit has clang-12 as part of a g++-11 | clang-12 | g++-10 | clang-11 | ... clause, with g++-11 the preferred dependency

Finally, I propose to remove src:opencl-clang-12 and src:spirv-llvm-translator-12, seeing as:

❯ reverse-depends -a source src:opencl-clang-12
No reverse dependencies found

❯ reverse-depends src:opencl-clang-12
No reverse dependencies found

❯ reverse-depends -a source src:spirv-llvm-translator-12
Reverse-Build-Depends
* opencl-clang-12 (for libllvmspirvlib-12-dev)

❯ reverse-depends src:spirv-llvm-translator-12
Reverse-Depends
* libopencl-clang12 (for libllvmspirvlib12)

[Steve Langasek (vorlon)]

Removing packages from kinetic:
 opencl-clang-12 12.0.0-4 in kinetic
  libopencl-clang-12-dev 12.0.0-4 in kinetic amd64
  libopencl-clang-12-dev 12.0.0-4 in kinetic arm64
  libopencl-clang-12-dev 12.0.0-4 in kinetic armhf
  libopencl-clang-12-dev 12.0.0-4 in kinetic ppc64el
  libopencl-clang-12-dev 12.0.0-4 in kinetic riscv64
  libopencl-clang-12-dev 12.0.0-4 in kinetic s390x
  libopencl-clang12 12.0.0-4 in kinetic amd64
  libopencl-clang12 12.0.0-4 in kinetic arm64
  libopencl-clang12 12.0.0-4 in kinetic armhf
  libopencl-clang12 12.0.0-4 in kinetic ppc64el
  libopencl-clang12 12.0.0-4 in kinetic riscv64
  libopencl-clang12 12.0.0-4 in kinetic s390x
Comment: Obsoleted by intel-opencl-clang, removed from Debian testing, broken with glibc 2.36; LP: #1987623
1 package successfully removed.

[Steve Langasek (vorlon)]

Removing packages from kinetic:
 spirv-llvm-translator-12 12.0.0-4 in kinetic
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic amd64
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic arm64
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic armhf
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic ppc64el
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic riscv64
  libllvmspirvlib-12-dev 12.0.0-4 in kinetic s390x
  libllvmspirvlib12 12.0.0-4 in kinetic amd64
  libllvmspirvlib12 12.0.0-4 in kinetic arm64
  libllvmspirvlib12 12.0.0-4 in kinetic armhf
  libllvmspirvlib12 12.0.0-4 in kinetic ppc64el
  libllvmspirvlib12 12.0.0-4 in kinetic riscv64
  libllvmspirvlib12 12.0.0-4 in kinetic s390x
  llvm-spirv-12 12.0.0-4 in kinetic amd64
  llvm-spirv-12 12.0.0-4 in kinetic arm64
  llvm-spirv-12 12.0.0-4 in kinetic armhf
  llvm-spirv-12 12.0.0-4 in kinetic ppc64el
  llvm-spirv-12 12.0.0-4 in kinetic riscv64
  llvm-spirv-12 12.0.0-4 in kinetic s390x
Comment: Obsoleted by spirv-llvm-translator, removed from Debian testing, broken with glibc 2.36; LP: #1987623
1 package successfully removed.

[Steve Langasek (vorlon)]

Removing packages from kinetic:
 llvm-toolchain-12 1:12.0.1-21 in kinetic
  clang-12 1:12.0.1-21 in kinetic amd64
  clang-12 1:12.0.1-21 in kinetic arm64
  clang-12 1:12.0.1-21 in kinetic armhf
  clang-12 1:12.0.1-21 in kinetic i386
  clang-12 1:12.0.1-21 in kinetic ppc64el
  clang-12 1:12.0.1-21 in kinetic riscv64
  clang-12 1:12.0.1-21 in kinetic s390x
  clang-12-doc 1:12.0.1-21 in kinetic amd64
  clang-12-doc 1:12.0.1-21 in kinetic arm64
  clang-12-doc 1:12.0.1-21 in kinetic armhf
  clang-12-doc 1:12.0.1-21 in kinetic i386
  clang-12-doc 1:12.0.1-21 in kinetic ppc64el
  clang-12-doc 1:12.0.1-21 in kinetic riscv64
  clang-12-doc 1:12.0.1-21 in kinetic s390x
  clang-12-examples 1:12.0.1-21 in kinetic amd64
  clang-12-examples 1:12.0.1-21 in kinetic arm64
  clang-12-examples 1:12.0.1-21 in kinetic armhf
  clang-12-examples 1:12.0.1-21 in kinetic i386
  clang-12-examples 1:12.0.1-21 in kinetic ppc64el
  clang-12-examples 1:12.0.1-21 in kinetic riscv64
  clang-12-examples 1:12.0.1-21 in kinetic s390x
  clang-format-12 1:12.0.1-21 in kinetic amd64
  clang-format-12 1:12.0.1-21 in kinetic arm64
  clang-format-12 1:12.0.1-21 in kinetic armhf
  clang-format-12 1:12.0.1-21 in kinetic i386
  clang-format-12 1:12.0.1-21 in kinetic ppc64el
  clang-format-12 1:12.0.1-21 in kinetic riscv64
  clang-format-12 1:12.0.1-21 in kinetic s390x
  clang-tidy-12 1:12.0.1-21 in kinetic amd64
  clang-tidy-12 1:12.0.1-21 in kinetic arm64
  clang-tidy-12 1:12.0.1-21 in kinetic armhf
  clang-tidy-12 1:12.0.1-21 in kinetic i386
  clang-tidy-12 1:12.0.1-21 in kinetic ppc64el
  clang-tidy-12 1:12.0.1-21 in kinetic riscv64
  clang-tidy-12 1:12.0.1-21 in kinetic s390x
  clang-tools-12 1:12.0.1-21 in kinetic amd64
  clang-tools-12 1:12.0.1-21 in kinetic arm64
  clang-tools-12 1:12.0.1-21 in kinetic armhf
  clang-tools-12 1:12.0.1-21 in kinetic i386
  clang-tools-12 1:12.0.1-21 in kinetic ppc64el
  clang-tools-12 1:12.0.1-21 in kinetic riscv64
  clang-tools-12 1:12.0.1-21 in kinetic s390x
  clangd-12 1:12.0.1-21 in kinetic amd64
  clangd-12 1:12.0.1-21 in kinetic arm64
  clangd-12 1:12.0.1-21 in kinetic armhf
  clangd-12 1:12.0.1-21 in kinetic i386
  clangd-12 1:12.0.1-21 in kinetic ppc64el
  clangd-12 1:12.0.1-21 in kinetic riscv64
  clangd-12 1:12.0.1-21 in kinetic s390x
  libc++-12-dev 1:12.0.1-21 in kinetic amd64
  libc++-12-dev 1:12.0.1-21 in kinetic arm64
  libc++-12-dev 1:12.0.1-21 in kinetic armhf
  libc++-12-dev 1:12.0.1-21 in kinetic i386
  libc++-12-dev 1:12.0.1-21 in kinetic ppc64el
  libc++-12-dev 1:12.0.1-21 in kinetic riscv64
  libc++-12-dev 1:12.0.1-21 in kinetic s390x
  libc++1-12 1:12.0.1-21 in kinetic amd64
  libc++1-12 1:12.0.1-21 in kinetic arm64
  libc++1-12 1:12.0.1-21 in kinetic armhf
  libc++1-12 1:12.0.1-21 in kinetic i386
  libc++1-12 1:12.0.1-21 in kinetic ppc64el
  libc++1-12 1:12.0.1-21 in kinetic riscv64
  libc++1-12 1:12.0.1-21 in kinetic s390x
  libc++abi-12-dev 1:12.0.1-21 in kinetic amd64
  libc++abi-12-dev 1:12.0.1-21 in kinetic arm64
  libc++abi-12-dev 1:12.0.1-21 in kinetic armhf
  libc++abi-12-dev 1:12.0.1-21 in kinetic i386
  libc++abi-12-dev 1:12.0.1-21 in kinetic ppc6...