A quick investigation reveals: * We have the "@" test (currently called command1 in the quoted log) which enables all crate features. The clang-sys crate does not permit enabling both the "runtime" and the "static" features at the same time, so the build script intentionally aborts with a compiler error. We will mark this test as FLAKY with the test_is_broken debcargo config flag for the next rust-clang-sys release. * The other tests fail because they attempt to run the `llvm-config` tool which isn't installed. I tested with the llvm and clang moved from the Recommends to the Depends field. This could be fixed by using the Depends field in the autopkgtests control. I don't know if debcargo is already able to output that field, maybe we have to implement it there first.