Clangs 19+ for AArch64 can't be used because of "LLVM"/"clang+llvm" confusion

[jwbee]

PR #461 looks as if it partially addresses this but the function llvm_release_name is still forcing clang 19 archives to be called "LLVM-...tar.xz" even though the archives for linux-aarch64 are named "clang+llvm-...tar.xz"

[helly25]

I improved on 471 in #472.

The new PR allows to not only automatically find the latest version it allows to restrict versions.

For instance the following would find any version starting with 19.1.1 but would not allow 19.1.7 (did not work for us) and would not accept any version starting with 20. Effectively allowing any newer version in the 19 branches but skipping 19.1.0 and 19.1.7.

llvm = use_extension("@toolchains_llvm//toolchain/extensions:llvm.bzl", "llvm", dev_dependency = True)
llvm.toolchain(
    name = "llvm_toolchain_llvm",
    llvm_version = "latest:>=19.1.1,!=19.1.7,<20",
)
use_repo(llvm, "llvm_toolchain_llvm")

[helly25]

Automatic distribution resolution has been reimplemented in #471 waiting for release.