build-environment: make some packages optional

Upgrading the s390x runner exposed some packages are not available for
it. Add an additional optional stage we only enable for arm64/x86_64
for now.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240426153938.1707723-2-alex.bennee@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
1 file changed