tree 9d1c6d2a899495ac5202912afba0d1f175a7feeb
parent 30f55067a6dcba602797c24e020a6a9c8ba22180
author Rich Felker <dalias@aerifal.cx> 1607962230 -0500
committer Rich Felker <dalias@aerifal.cx> 1607996173 -0500

fix VIDIOC_DQEVENT (v4l2) ioctl fallback for pre-5.6 kernels

commit 2412638bb39eb799b2600393bbd71cca8ae96bb2 got the size of struct
v4l2_event wrong and failed to account for the fact that the old
struct might be either 120 bytes with time misaligned mod 8, or 128
bytes with time aligned mod 8, due to the contained union having
64-bit members whose alignment is arch-dependent.

rather than adding new logic to handle the differences, use an actual
stripped-down version of the structure in question to derive the ioctl
number, size, and offsets.