[arch-general] race condition when upgrading the new ncurses package

[Dylan Scott]

> Pacman downloads all packages before installing any of them. So if you have
> a bad Internet connection then you'll be stuck at the first (download)
> step. It will not leave your system in broken state.

That's true. However, I broke my system pretty badly with this update.

I must have refreshed my package cache but not updated my system.
Probably with an aborted `pacman -Syu`.

Not realising the impact it would have, I later ran
`pacman -S rtorrent`.  This happily downloaded and installed the new
ncurses library, but not any of the other updated packages.

Anyway, this broke bash, zsh, xterm, gpgme, vim and more.

I had to turn off the PGP signature validation in pacman (without vi or
vim) and make sure not to close my working xterm and zsh sessions.

It was a pretty tense half-hour working it all out and restoring my
system. I got it sorted out in the end but I wouldn't be suprised if
someone else experiences something similar.