https://github.com/rust-lang/compiler-team/issues/378 (major change proposal to drop Windows XP support) notes this history and links to other relevant pages.
https://news.ycombinator.com/item?id=23313577
https://news.ycombinator.com/item?id=31112273
Doing such backward compatibility is definitiely possible for command-line tools. Once set up, it's automatic, and it needs extra testing after major changes.
https://github.com/mrk-its/rust-mos
It works, and builds binaries that are ready to be executed by Vice emulator.
https://minc.commandlinerevolution.nl/english/home.html
IronTCL for XP and up
https://minc.commandlinerevolution.nl/english/home.html
Updated SSL/TLS certs, again for XP and beyond:
Tiny Pascal-like language targetting DOS, CP/M and Unix:
https://t3x.org/t3x/0/index.html It's no Free Pascal but it can do good stuff with very little:
https://t3x.org/t3x/0/programs.html
JimTCL, a tiny TCL with bundled TLS, JSON, Sqlite3 and, optionally, some SDL2 support:
https://github.com/msteveb/jimtcl https://jim.tcl-lang.org/home/doc/www/www/index.html
You can compile JimTCL with MinC under XP, and maybe T3X0 too. With JimTCL you can build a quick TCL expect clone, some netcat clone too with TLS can be done in minutes too, really good for debugging or to create a simple IRC/Email/Gopher/Gemini client in text mode.