avoid MSVC NovCTP compiler crashes due to {} field initialization
skip sizeof checking for MSVC compiler
avoid unsupported constexpr (MSVC compiler crash)
skip fork&waits on Windows
avoid winsock redefinition errors (MSVC)
constexpr is still unsupported for classes on MSVC
replace missing gmtime_r on Windows
more detailed friend class specification
"multiple versions of defaulted function"
add supported mkdir