archivers/zstd (devel/llvm -> devel/cmake -> archivers/libarchive -> archivers/zstd), so ports-clang should not be used in zstd's COMPILER. Otherwise, zstd build is blocked if clang is not readily available, as is the case with bulk builds on gcc architectures. The dependency archivers/libarchive -> archivers/zstd was added recently. OK bket@ sthen@