[gpm]Data Sync

[Alessandro Rubini]

> My mouse (and many other) sends the 6th bit on. (d6, 8) on the first data
> byte. This is always on. according to mouse.4 man page, many other
> protocols do so. 

Exactly for that reason, the definition of a mouse type, in mice.c,
includes 4 bytes of "protocol": to check bit masks and resync with the
protocol.  Some protocols have key bits set (or unset) only in the
first byte and some other protocol don't.  If your protocol does but
it's not used than this is a bug in the definition of the type.

Please fix mice.c, not the main loop, and please send a patch even it
it's one line. Patches are generated and applied by tools, descriptions
must be written and applied by hand [this is "type-once use many"]

/alessandro