Earlier quoted context omitted.
Most people store their dot files (including their vim config) in a git repo and just check out a copy on any machine they use. That's what I do (git+stow). I can be up and running on a new system in just a few seconds.
Does anybody know a saner way of doing this cross-platform? I've resorted to doing platform checks in my .bashrc and don't get me started on the OSX / Linux differences in .platform, .bash_platform, and .bashrc sourcing. And when I tried termux on Android, oh dear lord. The whole thing breaks because of permissions issues. Had that issue on WSL too.
This is what I do, too. Most of mine is portable, but I have a block in bashrc that branches on uname.