Fix build failure

[cowlicks]

The build was failing with this:

$ cargo check
...
  --- stderr
  thread 'main' panicked at /home/blake/.cargo/registry/src/index.crates.io-6f17d22bba15001f/bindgen-0.55.1/src/ir/context.rs:838:9:
  "__atomic_wide_counter_struct_(unnamed_at_/usr/include/bits/atomic_wide_counter_h_28_3)" is not a valid Ident
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Looked the same as this bug. The fix was updating bindgen.

This PR updates bindgen to the latest version (0.69.4), and updated build.rs to reflect this change.
Basically all that was needed was a s/blacklist/blocklist/

p.s. I'm fixing this because it is downstream of hyperswarm-rs. That project is still dependent on this branch that derives Clone. cc @Frando any idea how much work applying your suggested changes there might be?