Do not run prepare() during integrity check

[cdown]

Fixed #645. This could cause some packages to fail to build, as patches
may be applied in prepare(), and re-running it would fail to apply those
patches.

[cdown]

Hmm... I notice this was actually intentionally removed in 40e4f07.

It's unclear to me what the right path is here, but I think reverting it seems a good idea for now.

[cdown]

(also, is it reasonable in general for prepare to affect pkgver? it strikes me as more niche than using prepare to patch)

[rmarquis]

Yes, this bug was indeed introduced in 40e4f07.

See this post for the rational behind it. Looks like it's not possible to support both scenario.

Edit: See #647 for the follow up of this PR.

[eli-schwartz]

As I said on the forums, it is "more correct", and really, you should want to respect the way makepkg works regardless of the likelihood of it mattering.
Especially since, in pacman-git, this behavior is explicitly documented. See:
https://git.archlinux.org/pacman.git/commit/?id=8454daa7feef14b660561f2434448d0b4ac0576d
https://git.archlinux.org/pacman.git/commit/?id=c034a3322b2a53fce51ffce144e36361892abeac
https://git.archlinux.org/pacman.git/commit/?id=59010386106eded2ee67798fa80215f250a53761

But the solution is much more basic. After running makepkg --nobuild to prepare the srcdir and check for pkgver updates, you should be building with --noextract as makepkg was explicitly designed to do. Or cleaning the srcdir.