sleep function still needed for MingW not MW-W64
include winsock2.h to resolve ws2tcpip.h conflict
fix for mingw-w64
Merge remote-tracking branch 'tonokip/master'
build/mingw: style fixup after tonobitc merge.

Use `#defined(...)` instead of `#defined ...`.

Remove comments about issues - anyone removing those lines can check blame
to see why they were added.

Add tonobitc to AUTHORS.md.