David Strobach authored Nov 17, 2016 and Peter Hutterer committed Nov 21, 2016

Sometimes it may be desirable to remap physical middle button
to something else and use emulation instead. The emulation is
however hardcoded to emulate physical button 2, so the emulated
button gets remapped together with the physical one. This patch
adds the Emulate3Button configuration option to allow for user
selection of the emulated button number and a configuration
like this:

Section "InputClass"
    Identifier "Middle button emulation config"
    MatchProduct ".... some device ..."
    MatchDriver "evdev"
    Option "Emulate3Buttons" "on"
    Option "Emulate3Button" "9"
EndSection

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>