[Xcb] Vendor Requests in GLX

[Jeremy Kolb]

I'm going through the extension registry and adding support for vendor 
glx extensions.  A lot of them just set up new GLX requests which is 
easy to do, but others use VendorPrivate/VendorPrivateWithReply. 
Basically you call GLXVendorPrivate with a vendor code, context_tag and 
then a list of data.  So the layout looks like this:

DeleteProgramsARB
      1           CARD8           opcode (X assigned)
      1           17              GLX opcode (glXVendorPrivateWithReply)
      2           4+n             request length
      4           1294            vendor specific opcode
      4           GLX_CONTEXT_TAG context tag
      4           INT32           n
      n*4         LISTofCARD32    programs


Mesa sets up a VendorPrivate request and then memcpys everything into a 
buffer to send just like they do with normal requests.  So how should I 
add these? Make a struct for each and then convert it to a (BYTE *) and 
pass it in?

Jeremy