[Xcb] More on types and xml-xcb

[Jeremy Kolb]

I just added support for float and double in c-client.xsl... I hope you 
don't mind Josh :)

This brings me to another point.  I've run into this a few times with 
type names.  For instance if I want "XCBGlxPixmap" and there's already 
an XCBPixmap #defined in xproto.h I get an error about Pixmap being 
defined multiple times.  Can we add an option so that it uses the "newly 
defined" type instead? Maybe something like <xidtype name="Pixmap" 
newname="true"/> or something?  I guess it would also have to go in 
enums, structs, typedefs as well.

Since PIXMAP and Pixmap are already used I'd have to use something like 
GLXPIXMAP which will give me XCBGlxGLXPIXMAP which is kind of cumbersome.

Any thoughts on this?

Jeremy