glx: Add glx_screen_vtable::create_context_attribs

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

src/glx/dri2_glx.c

@@ -857,7 +857,8 @@ dri2BindExtensions(struct dri2_screen *psc, const __DRIextension **extensions)
 }
 
 static const struct glx_screen_vtable dri2_screen_vtable = {
-   dri2_create_context
+   dri2_create_context,
+   NULL
 };
 
 static struct glx_screen *

src/glx/dri_glx.c

@@ -836,7 +836,8 @@ driBindExtensions(struct dri_screen *psc, const __DRIextension **extensions)
 }
 
 static const struct glx_screen_vtable dri_screen_vtable = {
-   dri_create_context
+   dri_create_context,
+   NULL
 };
 
 static struct glx_screen *

src/glx/glxclient.h

@@ -468,6 +468,14 @@ struct glx_screen_vtable {
 					 struct glx_config *config,
 					 struct glx_context *shareList,
 					 int renderType);
+
+   struct glx_context *(*create_context_attribs)(struct glx_screen *psc,
+						 struct glx_config *config,
+						 struct glx_context *shareList,
+						 unsigned num_attrib,
+						 const uint32_t *attribs,
+						 unsigned *error);
+
 };
 
 struct glx_screen

src/glx/indirect_glx.c

@@ -437,7 +437,8 @@ indirect_create_context(struct glx_screen *psc,
 }
 
 struct glx_screen_vtable indirect_screen_vtable = {
-   indirect_create_context
+   indirect_create_context,
+   NULL
 };
 
 _X_HIDDEN struct glx_screen *