Skip typedef of "char" to "STRING8" in xprint

Types "char" and "STRING8" are both handled specially as Java strings by
<list>s, so skip the parsing of such typedef in xprint.
Skip generation of GeGeneric event from xproto

xproto contains a GeGeneric event which stands for any event that uses
the generic event extension. However, GeGeneric itself is not a complete
event, so should not be generated.
Regenerate xproto

Regenerate xproto to remove the GeGeneric event.