POSIX Threads for Windows: https://sourceforge.net/projects/pthreads4w/

Code: https://git.code.sf.net/p/pthreads4w/code pthreads4w-code

Hash version: 44daa2441137b90477b449663abe9755b2c9a16b

Folder tests has been removed.

Add #include <stdint.h> to ptw32_relmillisecs.c and ptw32_timespec.c for MinGW build.
