gallium: remove unneeded st->haveFramebufferSurfaces field.

src/gallium/winsys/xlib/xm_api.c

@@ -814,9 +814,6 @@ XMesaContext XMesaCreateContext( XMesaVisual v, XMesaContext share_list )
    mesaCtx->Const.CheckArrayBounds = GL_TRUE;
 #endif
 
-   /* finish up xmesa context initializations */
-   c->st->haveFramebufferSurfaces = GL_TRUE;
-
    return c;
 }
 

src/mesa/state_tracker/st_cb_drawpixels.c

@@ -1017,11 +1017,7 @@ st_CopyPixels(GLcontext *ctx, GLint srcx, GLint srcy,
       srcy = ctx->DrawBuffer->Height - srcy - height;
    }
 
-   /* For some drivers (like Xlib) it's not possible to treat the
-    * front/back color buffers as surfaces (they're XImages and Pixmaps).
-    * So, this var tells us if we can use surface_copy here...
-    */
-   if (st->haveFramebufferSurfaces && srcFormat == texFormat) {
+   if (srcFormat == texFormat) {
       /* copy source framebuffer surface into mipmap/texture */
       pipe->surface_copy(pipe,
                          FALSE,

src/mesa/state_tracker/st_context.c

@@ -128,8 +128,6 @@ st_create_context_priv( GLcontext *ctx, struct pipe_context *pipe )
 
    st->ctx->VertexProgram._MaintainTnlProgram = GL_TRUE;
 
-   st->haveFramebufferSurfaces = GL_TRUE;
-
    st->pixel_xfer.cache = _mesa_new_program_cache();
 
    /* GL limits and extensions */

src/mesa/state_tracker/st_context.h

@@ -111,12 +111,6 @@ struct st_context
    char vendor[100];
    char renderer[100];
 
-   /** Can we access the front/back color buffers as pipe_surfaces?
-    * We can't with the Xlib driver...
-    * This is a hack that should be fixed someday.
-    */
-   GLboolean haveFramebufferSurfaces;
-
    /* State to be validated:
     */
    struct st_tracked_state **atoms;