When building for an architecture different from the host, the correct
old package was downloaded as "$copydir"'s pacman was configured with
the target CARCH, but checkpkg doesn't know this and tries to search the
cache for host CARCH instead, producing the following error:
`==> ERROR: tarball not found for package: xxx`
This change fixes this by passing the appropriate makepkg config
explicitly, so that checkpkg behaves consistently.
Co-Authored-by: Levente Polyak <anthraxx@archlinux.org>
Signed-off-by: Levente Polyak <anthraxx@archlinux.org>