At least in neovim, `│vi:` is not recognized as a modeline because it
has no preceding whitespace. After fixing this, opening a file yields
an error because `net` is not an option. (`noet`, however, is.)
OpenBSD's qsort() function is more secure than the ones used by
FreeBSD, NetBSD and MacOS. The best part is it goes faster too!
This change also imports the OpenBSD mergesort() and heapsort()