gallium: Add new PIPE_CAP_CL_GL_SHARING

We have a situation where some drivers have all the required features,
but they are not working with gl_sharing, so we end up advertising it
wrongly. Add this cap to ensure this driver was tested to work with
cl_khr_gl_sharing.

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26071>

docs/gallium/screen.rst

@@ -564,6 +564,8 @@ The integer capabilities:
     1. ``DRM_PRIME_CAP_IMPORT``: resource_from_handle is supported
     2. ``DRM_PRIME_CAP_EXPORT``: resource_get_handle is supported
 
+* ``PIPE_CAP_CL_GL_SHARING``: True if driver supports everything required by a frontend implementing the CL extension, and
+  also supports importing/exporting all of pipe_texture_target via dma buffers.
 * ``PIPE_CAP_PREFER_COMPUTE_FOR_MULTIMEDIA``: Whether VDPAU, VAAPI, and
   OpenMAX should use a compute-based blit instead of pipe_context::blit and compute pipeline for compositing images.
 * ``PIPE_CAP_FRAGMENT_SHADER_INTERLOCK``: True if fragment shader interlock

src/gallium/auxiliary/util/u_screen.c

@@ -451,6 +451,9 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
       return 0;
 #endif
 
+   case PIPE_CAP_CL_GL_SHARING:
+      return 0;
+
    case PIPE_CAP_TEXTURE_SHADOW_MAP: /* Enables ARB_shadow */
       return 1;
 

src/gallium/include/pipe/p_defines.h

@@ -861,6 +861,7 @@ enum pipe_cap
    PIPE_CAP_IMAGE_STORE_FORMATTED,
    PIPE_CAP_THROTTLE,
    PIPE_CAP_DMABUF,
+   PIPE_CAP_CL_GL_SHARING,
    PIPE_CAP_PREFER_COMPUTE_FOR_MULTIMEDIA,
    PIPE_CAP_FRAGMENT_SHADER_INTERLOCK,
    PIPE_CAP_FBFETCH_COHERENT,