Allocate keyboard and mouse event buffers in the device private structures.

Also simplify GetEvents functions.

Allocate X68kMousePriv dynamically to avoid static buffers.

DEVICE_OFF and DEVICE_CLOSE operations are also adjusted.

Reduce references to x68kKbdPriv and x68kMousePriv for readability.

Refactor X68k input device handling to remove SIGIO based event processing.

The keyboard and pointer input events are now processed directly
using fd event notifications registered via DIX SetNotifyFd(),
instead of the legacy SIGIO-based asynchronous I/O.

Use consistent name for DeviceIntPtr variables among keyboard and mouse.

Initialize DDX pointer valuators consistently with other drivers/servers.

This may not be strictly necessary, since InitValuatorAxisStruct()
for all axes is also called from the DIX InitPointerDeviceStruct()
via InitValuatorClassDeviceStruct() with default values.

However, for future X.Org updates, it is beneficial to keep the
DIX-DDX interface implementation in MouseProc's DEVICE_INIT operation
consistent with the official xf86-input-mouse driver, xquartz DDX server,
and others.

Properly apply DIX locking to input events in NetBSD-specific DDX servers.

This thread-based DIX locking approach using input_lock() and
input_unlock() has been available since X.Org 1.19.0:
https://gitlab.freedesktop.org/xorg/xserver/-/commit/30ac7567980a1eb79d084a63e0e74e1d9a3af673

All xfree86 DDX implementations have switched to using these new
DIX locks instead of the old OsBlockSIGIO() / OsReleaseSIGIO() methods:
https://gitlab.freedesktop.org/xorg/xserver/-/commit/6a5a4e60373c1386b311b2a8bb666c32d68a9d99

The xquartz DDX (an official X.Org server implementation) also uses
these locks for input events:
https://gitlab.freedesktop.org/xorg/xserver/-/commit/7d6ebf3f4e4d517bb846d15a5deb131da19a267c

This should resolve occasional SIGSEGVs in the Xsun server caused
by NULL pointer dereferences around the event queue handlers
under heavy load.

Should be pulled up to netbsd-10.

Fixes "FatalError re-entered, aborting" error when Xservers get SIGSEGV.

Handle a new DEVICE_ABORT mode perperly in deviceProc funtions.
Also don't exit via FatalError() on an unknown mode because it looks
upstream assumes DDX deviceProc functions don't treat it fatal:
https://gitlab.freedesktop.org/xorg/xserver/-/commit/9f79e93b6b3416055d08a0e8f9f16d5fd0649e36

ErrorF() doesn't append newlines at the end of messages.

Add "Emulate3Buttons" support to the X68k Xorg based monolithic server.

Based on "Emulate3Buttons" functions in the xf86-input-mouse driver,
with various refactoring and cleanups:
- rewrite a magic three-dimensional array for a finate state machine
with proper named structures etc.
- separate 3 button emulation functions from other stuff

See my post on port-x68k@ (and tech-x11@) for more details:
https://mail-index.netbsd.org/port-x68k/2021/02/05/msg000074.html

valuator_mask_zero() is enough for mouse button events.

Replace 'pointer' type with 'void *' to sync with upstream manner.

https://cgit.freedesktop.org/xorg/xserver/commit/?id=60014a4a98ff924ae7f6840781f768c1cc93bbab

TAB/space cleanup.

Update for removal of AddEnabledDevice and RemoveEnabledDevice.

Use the NotifyFd API instead as per upstream commits:
https://cgit.freedesktop.org/xorg/xserver/commit/?id=55c2e1a3aa587c58a74066724e11e30b3df267b8
https://cgit.freedesktop.org/xorg/xserver/commit/?id=be5a513fee6cbf29ef7570e57eb0436d70fbd88c
https://cgit.freedesktop.org/xorg/xserver/commit/?id=60a91031d13e4d29c383087120e318f6b528b6e5
https://cgit.freedesktop.org/xorg/xserver/commit/?id=7def2fea30060d47780dc1eedc91fada5ae1934f

Remove clause 3 and 4 from X68k server files written by Yasushi Yamasaki.

I've finally contacted with Yamasaki-san and he kindly answered
"no objection to change them to 2 clause license" in private mail.
Diffs to be committed have also been confirmed by him.
We appreciate all his contribution to early NetBSD/x68k.

Pull more changes from Xnest to adapt X68k to Xorg server 1.18.

- use QueueKeyboardEvents() and QueuePointerEvents() which are provided
by dix/getevents.c, instead of raw mieqEnqueue() with uninitialized
local InternalEvent
- remove now actually unused local InternalEvent
- explicitly call mieqFini() in DDX CloseInput()

Confirmed working on XM6i, and "please commit" from mrg@.

port to xorg-server 1.18. builds and may work, but not tested.

Port the ancient Xsun based monolithic MD X68k server to X11R7, like Xnest.

Most diffs (API changes from xfree to xorg and some WARNSfy)
are mechanical. Confirmed working on X68030 and XM6i.

See my post on port-x68k@ for details:
http://mail-index.netbsd.org/port-x68k/2014/02/27/msg000043.html