Find version-suffixed LLVM/Clang binutils on Debian

Debian rename all LLVM/Clang binaries with a version suffix to allow multiple versions installed at the same time. While there is a version agnostic package adds symlink to providing the standard binary names, if only the versionned packages are installed, binaries must be looked as 'binary-x.y'. In any case, using the same version of the binutils as the compiler seems better.