Broken package for empty package with post-install when built on btrfs

APKBUILD:

pkgname=foobar
pkgver=1
pkgrel=0
pkgdesc="Foobar"
url="https://example.org/"
arch="all"
license="WTFPL"
install="$pkgname.post-install"
options="!check"
package() {
        mkdir -p "$pkgdir"
}
sha512sums=""

foobar.post-install:

#!/bin/sh
echo "foobar!"

Build this on a btrfs partition and the resulting .PKGINFO in the apk will have size = 0 set instead of size = 4096 when built on ext4. This causes apk to classsify this as virtual package and not run the post-install.

A similar issue was fixed with 29557a4a but as this package doesn't install any files this if doesn't apply. It only contains a post-install which gets added to the directory later in the build process.