makekeys: handle the new _EVDEVK xorgproto symbols
These keys are all defined through a macro in the form: #define XF86XK_BrightnessAuto _EVDEVK(0x0F4)
The _EVDEVK macro is simply an offset of 0x10081000. Let's parse these lines correctly so those keysyms end up in our hashtables.
Fixes #137 (closed)