Detect if SO is Windows or Linux

#if defined(WIN32) || defined(_WIN32) || defined(__WIN32) || defined(__WIN32__) || defined(__TOS_WIN__) || defined(__WINDOWS__) && !defined(__CYGWIN__)
    #define OS_Windows
#else
    #define OS_Linux
#endif

bool main() {
    #ifdef OS_Windows
        /* Windows code */
    #else
        /* GNU/Linux code */
    #endif
    return true;
}