main/adsp-audio: add openrc subpackage (MR 5555)

main/adsp-audio/APKBUILD

 # Maintainer: Luca Weiss <luca@lucaweiss.eu>
 pkgname=adsp-audio
 pkgver=1
-pkgrel=3
+pkgrel=4
 pkgdesc="Init script for enabling the adsp audio subsystem (downstream Android kernels)"
 url="https://gitlab.com/postmarketOS/pmaports"
 arch="noarch"
 license="GPL-3.0-or-later"
-install="$pkgname.post-install"
 source="$pkgname.initd"
+subpackages="$pkgname-openrc"
 
 package() {
 	install -Dm755 "$srcdir"/$pkgname.initd "$pkgdir"/etc/init.d/adsp-audio
 }
+
+openrc() {
+	install="$subpkgname.post-install"
+	default_openrc
+}
+
 sha512sums="1edd94b45d37d82b37e04a4f3ff9f3c116bee088a0f83c7b605a0107a3da4f5c9f7d0c1a50c082eb05914352979114135bde8942be9f6ac4fe3a7041e9190bc3  adsp-audio.initd"