community/dracut: prefer busybox inside the generated initramfs

Only include bash into the generated initramfs if a dracut module
explicitly depends on it.

Implemented as a new dracut module that picks busybox shell on alpine.

Based on the idea discussed upstream:
https://github.com/dracutdevs/dracut/pull/2368#issuecomment-1588285469

community/dracut/APKBUILD

@@ -2,7 +2,7 @@
 # Maintainer: Conrad Hoffmann <ch@bitfehler.net>
 pkgname=dracut
 pkgver=060
-pkgrel=0
+pkgrel=1
 _commit=856e7acdb1462803c2517c8d64afb2e34c73c735
 pkgdesc="An event driven initramfs infrastructure"
 url="https://github.com/dracutdevs/dracut/wiki"
@@ -14,7 +14,9 @@ options="!check" # There is a test suite, but it requires root/sudo
 triggers="$pkgname.trigger=/usr/share/kernel/*"
 source="$pkgname-$pkgver.tar.gz::https://github.com/dracutdevs/dracut/archive/$_commit.tar.gz
 	README.alpine
-	10-alpine.conf"
+	10-alpine.conf
+	initramfs-shell.patch
+	"
 provides="initramfs-generator"
 provider_priority=100 # low, somewhat experimental
 builddir="$srcdir"/$pkgname-$_commit
@@ -92,4 +94,5 @@ sha512sums="
 0cd2fefcd624758063c77836989260a3d5b0d533004c2395124c8200c31602f5d7d0b8c9491de37ce4afb2c5009b2cf944ddd3bb9e0e11120d84176cb1e7423c  dracut-060.tar.gz
 fa1d65d8987d9b5846f5cd7989bc373ca4f9d787a3025284ce55e2d5439dce29f70bd75ff5e07bfa783548e080859ec8972b6887ec58993bc54a8dcc849066d6  README.alpine
 8688380dd77949d039a22a0dfb34c67cedd48b45a346a2e5f8b9ce9bd9872a8b1b9e06a51edf75d548b5072243afdb08d7ad25616a82cd030de432bb9e14da47  10-alpine.conf
+54d6292a5360145c135f670a5f69cf317e2e03c34495efc7c134c0bf68e09ae27c8cf9fc7434b9742f6dc6e230b0161566c25796956a4fdf35700cd34d1626e8  initramfs-shell.patch
 "

community/dracut/initramfs-shell.patch

+From adf7af3bebc1ccd24c16668ba161c30447db2df7 Mon Sep 17 00:00:00 2001
+From: Laszlo Gombos <laszlo.gombos@gmail.com>
+Date: Tue, 13 Jun 2023 13:16:12 +0000
+Subject: [PATCH] improve shell selection
+
+---
+ modules.d/00sh/module-setup.sh   | 17 +++++++++++++++++
+ modules.d/99base/module-setup.sh |  2 +-
+ 2 files changed, 18 insertions(+), 1 deletion(-)
+ create mode 100755 modules.d/00sh/module-setup.sh
+
+diff --git a/modules.d/00sh/module-setup.sh b/modules.d/00sh/module-setup.sh
+new file mode 100755
+index 0000000000..2495553e28
+--- /dev/null
++++ b/modules.d/00sh/module-setup.sh
+@@ -0,0 +1,17 @@
++#!/bin/sh
++
++depends() {
++    shells='dash bash mksh busybox'
++    for shell in $shells; do
++        if dracut_module_included "$shell"; then
++            echo "$shell"
++            return 0
++        fi
++    done
++
++    shell=$(realpath -e /bin/sh)
++    shell=${shell##*/}
++
++    echo "$shell"
++    return 0
++}
+diff --git a/modules.d/99base/module-setup.sh b/modules.d/99base/module-setup.sh
+index 54b0deb914..8798cb5aa4 100755
+--- a/modules.d/99base/module-setup.sh
++++ b/modules.d/99base/module-setup.sh
+@@ -7,7 +7,7 @@ check() {
+ 
+ # called by dracut
+ depends() {
+-    echo udev-rules
++    echo udev-rules sh
+     return 0
+ }
+