use CSI 14 t where TIOCGWINSZ ioctl isn't available

[dankamongmen]

on at least windows, i assume we don't have TIOCGWINSZ as an ioctl (maybe we do? who knows). when we move to support it, try using CSI 14 t to recover the window geometry in pixels. to use this as a substitute, we would need put it (and the resultant round trip) into notcurses_resize(), which is kinda lame, so look for a native call that includes this functionality.

[dankamongmen]

though it might be that neither of these will work with Windows Terminal: microsoft/terminal#8581

[WSLUser]

So in this case, I'd NOT use Windows Terminal as the base. Instead I'd look at the other terminals that run on Windows. Unfortunately though, since ConPTY doesn't have a pass-through mode, you're likely going to find very few terminal emulators capable of supporting this. MinTTY for example would be a terminal that completely supports these along with Sixel and may be your only viable option for testing. If you do choose to use that terminal, you don't need to install Cygwin or Msys2 to run it, the necessary dlls are included in WSLtty or Git bash.

Note: Some of the terminals existed prior to ConPTY so it's possible you could use the winpty mode instead to get these sequences working as I'd expect if those terminals support Sixel, they'd support the CSI 14 t sequence. If they don't....I'd raise an issue with them to do so when in winpty mode vice ConPTY mode with the expectation of moving that logic to work in ConPTY "Passthrough" Mode when it becomes available.

[dankamongmen]

thinking we might want to throw this into the initial queries, so we'll know when it's available?

[dankamongmen]

we're now sending CSI 14t in our initial query, and parsing the response. confirmed that it works.