It was hard to extend the option specification string passed to
getopt_long as the third argument.
The origian code had a branch with WITH_SELINUX ifdef condition. If
one wants to add one more option char with another ifdef condition
like ENABLE_SUBIDS to the spec, the one must enumerate the specs for
all combinations of the conditions:
* WITH_SELINUX && ENABLE_SUBIDS
* WITH_SELINUX && !ENABLE_SUBIDS
* !WITH_SELINUX && ENABLE_SUBIDS
* !WITH_SELINUX && !ENABLE_SUBIDS
With this change, you can append an option char to the spec.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>