glx: remove empty GLX_SGIX_swap_barrier stubs

The extension was never implemented. Quick search suggests:
 - no actual users (on my Arch setup)
 - the Nvidia driver does not implement the extension

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>

src/glx/apple/glx_empty.c

@@ -61,27 +61,6 @@ glXJoinSwapGroupSGIX(Display * dpy, GLXDrawable drawable, GLXDrawable member)
 }
 
 
-/*
-** GLX_SGIX_swap_barrier
-*/
-void
-glXBindSwapBarrierSGIX(Display * dpy, GLXDrawable drawable, int barrier)
-{
-   (void) dpy;
-   (void) drawable;
-   (void) barrier;
-}
-
-Bool
-glXQueryMaxSwapBarriersSGIX(Display * dpy, int screen, int *max)
-{
-   (void) dpy;
-   (void) screen;
-   (void) max;
-   return False;
-}
-
-
 /*
 ** GLX_OML_sync_control
 */

src/glx/glxcmds.c

@@ -2049,27 +2049,6 @@ __glXJoinSwapGroupSGIX(Display * dpy, GLXDrawable drawable,
 }
 
 
-/*
-** GLX_SGIX_swap_barrier
-*/
-static void
-__glXBindSwapBarrierSGIX(Display * dpy, GLXDrawable drawable, int barrier)
-{
-   (void) dpy;
-   (void) drawable;
-   (void) barrier;
-}
-
-static Bool
-__glXQueryMaxSwapBarriersSGIX(Display * dpy, int screen, int *max)
-{
-   (void) dpy;
-   (void) screen;
-   (void) max;
-   return False;
-}
-
-
 /*
 ** GLX_OML_sync_control
 */
@@ -2544,10 +2523,6 @@ static const struct name_address_pair GLX_functions[] = {
    /*** GLX_SGIX_swap_group ***/
    GLX_FUNCTION2(glXJoinSwapGroupSGIX, __glXJoinSwapGroupSGIX),
 
-   /*** GLX_SGIX_swap_barrier ***/
-   GLX_FUNCTION2(glXBindSwapBarrierSGIX, __glXBindSwapBarrierSGIX),
-   GLX_FUNCTION2(glXQueryMaxSwapBarriersSGIX, __glXQueryMaxSwapBarriersSGIX),
-
    /*** GLX_MESA_copy_sub_buffer ***/
    GLX_FUNCTION2(glXCopySubBufferMESA, __glXCopySubBufferMESA),
 

src/glx/glxextensions.c

@@ -161,7 +161,6 @@ static const struct extension_info known_glx_extensions[] = {
    { GLX(SGIS_multisample),            VER(0,0), Y, Y, N, N },
    { GLX(SGIX_fbconfig),               VER(1,3), Y, Y, N, N },
    { GLX(SGIX_pbuffer),                VER(1,3), Y, Y, N, N },
-   { GLX(SGIX_swap_barrier),           VER(0,0), N, N, N, N },
    { GLX(SGIX_swap_group),             VER(0,0), N, N, N, N },
    { GLX(SGIX_visual_select_group),    VER(0,0), Y, Y, N, N },
    { GLX(SGI_make_current_read),       VER(1,3), Y, N, N, N },

src/glx/glxextensions.h

@@ -67,7 +67,6 @@ enum
    SGIS_multisample_bit,
    SGIX_fbconfig_bit,
    SGIX_pbuffer_bit,
-   SGIX_swap_barrier_bit,
    SGIX_swap_group_bit,
    SGIX_visual_select_group_bit,
    SGI_make_current_read_bit,