Commit 00b64fca55 introduced configure
detection for HAVE_POSIX_IOCTL but unfortunately this conflicts with
v4l-utils version 1.30, which itself checks for #ifdef HAVE_POSIX_IOCTL
in a public header and erroneously determines it to be true because we
define this to be 0.
Since this is only used for avdevice/v4l2, we rename this to something
else, namely ioctl_posix, simply to prevent the name conflict with the
file /usr/include/libv4l2.h at least until they can upstream a fix on
their end.
Signed-off-by: Leo Izen <leo.izen@gmail.com>