udev: spelling fixes
Use strlen even for constant strings

GCC optimizes strlen("string constant") to a constant, even with -O0.
Thus, replace patterns like sizeof("string constant")-1 with
strlen("string constant") where possible, for clarity.  In particular,
for expressions intended to add up the lengths of components going into
a string, this often makes it clearer that the expression counts the
trailing '\0' exactly once, by putting the +1 for the '\0' at the end of
the expression, rather than hidden in a sizeof in the middle of the
expression.
udev: properly detect reference to unexisting part of PROGRAM's result
input_id: Recognize buttonless joystick types

Input devices like rudders or pedals are joystick-like; they don't have
buttons, but axes like RX, THROTTLE, or RUDDER. These don't interfere with
other device types with absolute axes (touch screens, touchpads, and
accelerometers), so it's fairly safe to mark them as ID_INPUT_JOYSTICK and thus
hand out dynamic ACLs to the user.

https://bugs.freedesktop.org/show_bug.cgi?id=70734
UPSTREAM.notes: updated

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>