[RFC] DIX changes to support adding XWin DDX AIGLX

[Jon TURNEY]

I have done a rewrite of the Xwin DDX AIGLX code to actually make it do
something useful again, which requires a few minor DIX changes, offered
for comment here.

The actual XWin DDX changes aren't in this patch-set because they are
probably only of niche interest, and reasonably large.  They are available at 
http://cgit.freedesktop.org/~jturney/xserver/log/?h=cygwin-aiglx-for-master 

Jon TURNEY (5):
  Replace DDXBEFORERESET with a more general way of doing DDX-specific
    hooks
  Add a DDX specific GLX provider push hook
  Do not create visuals for fbConfigs which don't support window
    drawables.
  Move GLX extension string utility functions into the GLX extension
  Let configure --enable/disable-aiglx control building of AIGLX for
    all DDXs

 configure.ac                   |   15 ++++++++-------
 dix/dispatch.c                 |    7 ++++---
 glx/Makefile.am                |    8 ++++----
 glx/glxscreens.c               |    4 ++++
 hw/dmx/dmxinit.c               |    6 ------
 hw/vfb/InitOutput.c            |    7 -------
 hw/xfree86/dixmods/Makefile.am |    2 +-
 hw/xnest/Init.c                |    6 ------
 hw/xwin/InitOutput.c           |    9 ++++++---
 include/ddxhooks.h             |   38 ++++++++++++++++++++++++++++++++++++++
 include/dix-config.h.in        |    3 ---
 include/os.h                   |    4 ----
 mi/miinitext.c                 |   11 ++++++++++-
 13 files changed, 75 insertions(+), 45 deletions(-)
 create mode 100644 include/ddxhooks.h