subsystems capabilities:
_SC_AIO_LISTIO_MAX returns the default of _POSIX_AIO_LISTIO_MAX
_SC_AIO_MAX returns the default _POSIX_AIO_MAX
_SC_AIO_PRIO_DELTA_MAX returns the default of 0
Without these adjustments the values returned are -1 even when the
aio side of the kernel returns '0' for them which is incorrect.
Noticed by: Craig Rodrigues <rodrigc@attbi.com>