The tests done on /usr/tests/usr.sbin/jail were failing. The command 'jls -n' was giving segmentation fault in the last releases(13) for powerpc.
The problem happens when the quoted_print function is called with an empty value for the 'value' parameter.
In fact, if the 'value' parameter is empty, the behavior is different in powerpc (key=(null)"" (tested in an old release)) and amd64 (key=/""}""), but it should be the same.
With the correction proposed in the patch, the segmentation fault no longer occurs and the behavior is the same for powerpc and amd64 (key=""), as commented in the code 'An empty string needs quoting'.