PIPE-ing stderr in Windows with `--height` causes `--height option is currently not supported on this platform`

[justfoolingaround]

• [x] I have read through the manual page (man fzf)
• [x] I have the latest version of fzf
• [x] I have searched through the existing issues

Info

• OS
  • [ ] Linux
  • [ ] Mac OS X
  • [x] Windows
  • [ ] Etc.
• Shell
  • [x] bash
  • [ ] zsh
  • [ ] fish

Problem / Steps to reproduce

I'm using cmd and Python for the sake of demonstration, piping to anything else, fzf too will cause the same problem.

fzf --height=50% 2>&1 | py -c "print(__import__('sys').stdin.read())"

Notice that,

fzf --height=50%
fzf --height=50% 2>&1
fzf --height=50% | py -c "print(__import__('sys').stdin.read())"

works just fine.

I'm sorry for the edits, I accidentally hit "New Issue" while typing.

[justchokingaround]

same behavior on mac

[junegunn]

fzf prints its UI using STDERR, and prints the selected item to STDOUT. So redirecting STDERR will surely break it.