Arch Linux

Makepkg (as of pacman 4.2) now verifies GPG signed files differently. They require a reference to the signer's fingerprint. Without that, makepkg's integrity check will fail.

For an example of a good pkgbuild, curl has the following lines:
source=("http://curl.haxx.se/download/$pkgname-$pkgver.tar.gz"{,.asc}
curlbuild.h)
md5sums=('88c5650122873712296d4b1db3f12e6c'
'SKIP'
'751bd433ede935c8fae727377625a8ae')
validpgpkeys=('914C533DF9B2ADA2204F586D78E11C6B279D5C91') # Daniel Stenberg

More details are under the 'validpgpkeys' of the pkgbuild man page. The fingerprint can be generated with
gpg --fingerprint <key-identifier or user ID>

This is not exactly critical, but catching it now may save some bug reports and user frustration. No rebuild is necessary, simply updating the pkgbuilds should be sufficient.

The package list was generated by finding the difference between
egrep -R '\.(asc|sig)' /var/abs | cut -d '/' -f 5 | sort -u
and
grep -R 'validpgpkeys' /var/abs | cut -d '/' -f 5 | sort -u
and so may have a false positive if you recently fixed this in SVN.