Re: Emulate3Buttons support for X68k Xorg server

Committed.

 https://mail-index.netbsd.org/source-changes/2021/02/07/msg126716.html
 https://mail-index.netbsd.org/source-changes/2021/02/07/msg126719.html
 https://mail-index.netbsd.org/source-changes/2021/02/07/msg126720.html
 https://mail-index.netbsd.org/source-changes/2021/02/07/msg126721.html

I've also put a "pseudo" diff for xf86-input-mouse/dist/src/mouse.c to
clarify how the "magic three-dimensional array for a finate state machine"
was rewritten for a record:
 https://gist.github.com/tsutsui/cd45cdbbf2991722875d405f87a0983e

Note misc xf86 specific stuff were modified in prior revisions
(the original xf86PostButtonEvent() functions were replaced with
 the DIX QueuePointerEvents() for example), so this cannot be
applied as is.

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Izumi Tsutsui