pkg_set_string(oldpkg, PKG_PRIORITY, pkg_get_string(newpkg, PKG_PRIORITY));
if (!pkg_get_string(oldpkg, PKG_SOURCE))
pkg_set_string(oldpkg, PKG_SOURCE, pkg_get_string(newpkg, PKG_SOURCE));
pkg_set_string(oldpkg, PKG_PRIORITY, pkg_get_string(newpkg, PKG_PRIORITY));
if (!pkg_get_string(oldpkg, PKG_SOURCE))
pkg_set_string(oldpkg, PKG_SOURCE, pkg_get_string(newpkg, PKG_SOURCE));