vim: Add C language snippets
vim: Add C language snippets

This has been sitting around in my worktree for a while now. Let's
commit it and get it out of the way.

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent