util: Removing `_MTX_INITIALIZER_NP` by moving all callers to `simple_mtx`
cc @okias now musl c11 threads can be used
cc @jenatali
- Removing
_MTX_INITIALIZER_NP
by moving all callers tosimple_mtx
- _MTX_INITIALIZER_NP is a fixed temporary hack, removed it always better and prevent future usage of it
- getting c11/threads.h to be consistence with the standard
Edited by Yonggang Luo