mesa: Rename gl_context::swtnl_im to vbo_context; use proper type.

The main GL context's swtnl_im field is the VBO module's vbo_context
structure.  Using the name "swtnl" in the name is confusing since
some drivers use hardware texturing and lighting, but still rely on the
VBO module for drawing.

v2: Forward declare the type and use that instead of void *
    (suggested by Eric Anholt).
v3: Remove unnecessary cast (pointed out by by Topi Pohjolainen).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

src/mesa/main/mtypes.h

@@ -80,6 +80,7 @@ struct prog_instruction;
 struct gl_program_parameter_list;
 struct set;
 struct set_entry;
+struct vbo_context;
 /*@}*/
 
 
@@ -3669,7 +3670,7 @@ struct gl_context
    void *swrast_context;
    void *swsetup_context;
    void *swtnl_context;
-   void *swtnl_im;
+   struct vbo_context *vbo_context;
    struct st_context *st;
    void *aelt_context;
    /*@}*/

src/mesa/vbo/vbo_context.c

@@ -152,7 +152,7 @@ GLboolean _vbo_CreateContext( struct gl_context *ctx )
 {
    struct vbo_context *vbo = CALLOC_STRUCT(vbo_context);
 
-   ctx->swtnl_im = (void *)vbo;
+   ctx->vbo_context = vbo;
 
    /* Initialize the arrayelt helper
     */
@@ -224,7 +224,7 @@ void _vbo_DestroyContext( struct gl_context *ctx )
       if (ctx->API == API_OPENGL_COMPAT)
          vbo_save_destroy(ctx);
       free(vbo);
-      ctx->swtnl_im = NULL;
+      ctx->vbo_context = NULL;
    }
 }
 

src/mesa/vbo/vbo_context.h

@@ -90,7 +90,7 @@ struct vbo_context {
 
 static inline struct vbo_context *vbo_context(struct gl_context *ctx) 
 {
-   return (struct vbo_context *)(ctx->swtnl_im);
+   return ctx->vbo_context;
 }