steven_blocks: error[E0425]: cannot find function pthread_atfork in crate libc

[iceiix]

cd blocks
cargo build

fails:

   Compiling rand v0.6.5
error[E0425]: cannot find function `pthread_atfork` in crate `libc`
   --> .cargo/registry/src/github.com-1ecc6299db9ec823/rand-0.6.5/src/rngs/adapter/reseeding.rs:320:28
    |
320 |             unsafe { libc::pthread_atfork(None, None, Some(fork_handler)) };
    |                            ^^^^^^^^^^^^^^ not found in `libc`

cargo tree shows rand v0.6.5 is used by cgmath and collision:

├── cgmath v0.17.0
│   ├── approx v0.3.2
│   │   └── num-traits v0.2.6
│   ├── num-traits v0.2.6 (*)
│   ├── rand v0.6.5
├── collision v0.20.1
│   ├── approx v0.3.2 (*)
│   ├── bit-set v0.5.0
│   │   └── bit-vec v0.5.0
│   ├── cgmath v0.17.0 (*)
│   ├── rand v0.6.5 (*)