Fix ‘TIOCSTI’ undeclared error on MSYS2

[rashil2000]

This value seems to be undefined in MSYS2 environments.

Needs to be manually defined.

Reference - dvorka/hstr@79781c1

[abishekvashok]

Seems good. Can someone with Cygwin help by doing a quick test of this path?

@rashil2000 this is no way an underestimation of this patch. I appreciate and thank you for the time you put into this issue. Thank you for working on it. I really want to get this merged however, I don't have any way of testing this.

I can merge this if someone, even you, tests this on Cygwin and reports whether this mitigates the issue. (Just to be sure)

[rashil2000]

Well, I went through the (painful) setup of installing Cygwin. The TIOCSTI error is gone now, but the LINES and COLS issue (elaborate discussion here #40) still persists. No idea how to solve that :(

I have renamed this PR to remove the mention of Cygwin, since it fixes only the MSYS2 issue.

[rashil2000]

Hey @abishekvashok, sorry for pinging but, is there anything that needs to be done for this PR?