Add support for loongarch64
As the upstream has supported loongarch64 since llvm16, this patch adds support to the llvm-toolchain-17 packages and also fixes the build failure on loong64[1].
The details are as follows:
- Do not try to install hwasan_symbolize on loong64
- Enable libunwind, lld, lldb and openmp on loong64
[1]https://buildd.debian.org/status/package.php?p=llvm-toolchain-17&suite=experimental
Edited by Chen Li