Maybe it would be better to simply stick to a mutex and condvar, as
libstd does. Optimization is for later anyway.

Otherwise it would be possible to do e.g.

`pthread_mutex_t mutex = PTHREAD_ONCE_INITIALIZER;```,
which would expand to
```pthread_mutex_t mutex = {0};```.

Fix mspaces not being protected by locks.

See merge request !387

termios adding cfsetspeed bsd extension which set both __c_ispeed/__c_ospeed fields

See merge request !385

Fix platform::errno = ... in signal.rs

See merge request !384

signal add fewer more implementations

See merge request !378

setsid implementation

See merge request !381

cfmakeraw implementation proposal

See merge request !382

Add no-op tzset, plus required static vars

See merge request !383

fix no_mangle annotation missing

See merge request !377

signal add few missing implementations

See merge request !376

sync implementation

See merge request !375

unistd: fdatasync implementation.

See merge request !373

stdlib: unlockpt implementation proposal

See merge request !372