package/dracut: fix dracut_wrapper

As reported by Thierry Bultel [1], dracut doesn't work since the
version bump to version 059.

Further investigation by Andreas Naumann [2] reported that the issue
come from this commit d010fa0 refactor(dracut-install): fork() instead
of popen(), sanitise line reading [3].

The issue come from our dracut_wrapper and how DRACUT_LDD is defined.
Indeed dracut expect DRACUT_LDD=ldd or a single binary (without
arguments) but we are using "prelink-rtld --root='${sysroot}'".

With the change introduced by [3], our DRACUT_LDD is used
directly by execlp() leading to an error:

  execlp(ldd, ldd, fullsrcpath, (char *)NULL);

Use mktemp to generate a temporary dracut-ldd script using
prelink-rtld --root='${sysroot}' ${1}

execute dracut.real in a subshell to cleanup the temporary file
at the end of the dracut wrapper script.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243423 [tests.fs.test_cpio.TestCpioDracutGlibcMergedUsr]
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243434 [tests.fs.test_cpio.TestCpioDracutMuslMergedUsr]
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243567 [tests.fs.test_cpio.TestCpioDracutUclibcMergedUsr]
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243559 [tests.fs.test_cpio.TestCpioDracutGlibc]
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243504 [tests.fs.test_cpio.TestCpioDracutUclibc]
https://gitlab.com/buildroot.org/buildroot/-/jobs/6224243498 [tests.fs.test_cpio.TestCpioDracutMusl]

[1] http://lists.busybox.net/pipermail/buildroot/2024-February/684145.html
[2] http://lists.busybox.net/pipermail/buildroot/2024-February/684503.html
[3] https://github.com/dracutdevs/dracut/commit/d010fa0d7f8ef42ad31729d027d2e4be6dd6e588

Fixes: 145f01ded5 ("package/dracut: bump to version 059")
Reported-by: Thierry Bultel <thierry.bultel@linatsea.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/dracut/dracut_wrapper

@@ -31,8 +31,18 @@ if [ -z "${sysroot}" ]; then
 fi
 
 topdir="$(dirname "$(realpath "$(dirname "${0}")")")"
-export DRACUT_LDD="${topdir}/sbin/prelink-rtld --root='${sysroot}'"
+DRACUT_LDD="$(mktemp /tmp/dracut-ldd.XXXXXX)"
+cat >"${DRACUT_LDD}" <<EOL
+#!/bin/bash
+${topdir}/sbin/prelink-rtld --root='${sysroot}' \${1}
+EOL
+chmod +x "${DRACUT_LDD}"
+export DRACUT_LDD
 export DRACUT_INSTALL="${topdir}/lib/dracut/dracut-install"
 export DRACUT_LDCONFIG=/bin/true
 export dracutbasedir="${topdir}/lib/dracut"
-exec "${topdir}/bin/dracut.real" "${@}"
+(exec "${topdir}/bin/dracut.real" "${@}")
+
+if [ -n "${DRACUT_LDD}" ]; then
+	rm -f "${DRACUT_LDD}"
+fi