Implement WinSock 1.1 fallback

[seritools]

This would make networking on NT 3.51 and older, and Windows 95 RTM without updates possible.

[seritools]

This should actually be pretty doable - other than read_vector/write_vectored there isn't much to do. 🤔

[cher-nov]

Someone backported curl 8.4.0 to Windows NT 3.51, translating WinSocks 1.1 to Winsock 2.x with their own homegrown wrapper. This might be useful at least as an example, I guess.

https://github.com/DaniElectra/winsock351
https://github.com/DaniElectra/curl9x
https://mstdn.social/@DaniElectra/112526436022212355

[seritools]

Thanks! will probably have to solve #46 first though.