Yes, Windows added some posix function to avoid portability issues. I think the Windows function are actually _dup and _dup2 (see <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/dup-dup2?view=vs-2019)>.
If people are interested in this, maybe there should be `dupFileHandle` and `dup2FileHandle` in `system/io` to makes things easier ?
