packaging/qemu: Build and package completely in the container

Currently QEMU is built inside the container, its tarball pulled to
the host, files removed then packaged again. Instead, let's run all
those steps inside the container and the resulting tarball will
be the final version. For that end, it is introduced the
qemu-build-post.sh script which will remove the uneeded files and
create the tarball.

The patterns for directories on qemu.blacklist had to be changed
to work properly with `find -path`.

Fixes #1168

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>

tools/packaging/static-build/scripts/qemu-build-post.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+#
+# Copyright (c) 2020 Red Hat, Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# This script process QEMU post-build.
+#
+set -e
+
+script_dir="$(realpath $(dirname $0))"
+source "${script_dir}/../qemu.blacklist"
+
+if [[ -z "${QEMU_TARBALL}" || -z "${QEMU_DESTDIR}" ]]; then
+	echo "$0: needs QEMU_TARBALL and QEMU_DESTDIR exported"
+	exit 1
+fi
+
+pushd "${QEMU_DESTDIR}"
+# Remove files to reduce the surface.
+echo "INFO: remove uneeded files"
+for pattern in ${qemu_black_list[@]}; do
+	find . -path "$pattern" | xargs rm -rfv
+done
+
+echo "INFO: create the tarball"
+tar -czvf "${QEMU_TARBALL}" *
+popd