This is the user/application API and does not include the kernel
interface. Definitions shared with the kernel are found in
<sys/quota.h>.
Since I've been working on a local branch I have taken the liberty of
moving the latest-so-far version of <quota.h> to the front of the
patch queue. This loses (a small amount of) history but has the
advantage of avoiding unnecessary version bumps of libquota.so.