Fix for missing choice.exe on XP

[brickviking]

Two changes here, one to work around the missing CHOICE.EXE command on XP, the other to prepare for a possible "wait until file downloads before we unarchive it" change.

I'm after some help here, is there a way of platform-independently waiting for a set amount of time on Windows XP? So far the only options I've seen for waiting have used timeout, which doesn't exist on XP, or ping, which is ugly, but does work as long as the machine has networking up. I only really need it to fetch the initial curl cab file by using Internet Explorer to download the file, as every version from 10 onwards appears to have curl.exe already installed as part of the base operating system files.

[brickviking]

We seem to have run into an obstacle for XP, that it can't successfully negotiate a secure connection to github, because the OS only supports TLS1.0 at the latest. There is an unverified way to get TLS1.1/1.2 installed along with Internet Explorer 8, but man, that's a long winded way of getting qb64 onto a system.

[DualBrain]

I think the idea is pretty good, but I would suggest that we create a new setup_winxp.cmd to make any of these changes specific to that target. This way anything that needs to be done for WinXP can be done (as I suspect there will be more necessary) without affecting newer versions of Windows (setup_win.cmd).