Linking to the NSS module directly does not work if the linker defaults
to --as-needed because it will remove the apparently unused DSO
reference and not generate a DT_NEEDED entry. Use an explicit dlopen
call, like in the other chroot tests involving NSS modules.
If /etc/aliases ends with a continuation line (a line that starts
with whitespace) which does not have a trailing newline character,
the file parser would crash due to a null pointer dereference.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>