Fix GL_EXT_packed_depth_stencil crash, but shadowtex still broken

src/mesa/drivers/dri/i915tex/intel_buffers.c

@@ -827,7 +827,7 @@ intel_draw_buffer(GLcontext * ctx, struct gl_framebuffer *fb)
     ***/
    if (fb->_DepthBuffer && fb->_DepthBuffer->Wrapped) {
       irbDepth = intel_renderbuffer(fb->_DepthBuffer->Wrapped);
-      if (irbDepth->region) {
+      if (irbDepth && irbDepth->region) {
          FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, GL_FALSE);
          depthRegion = irbDepth->region;
       }

src/mesa/drivers/dri/i915tex/intel_tex_format.c

@@ -136,6 +136,10 @@ intelChooseTextureFormat(GLcontext * ctx, GLint internalFormat,
    case GL_DEPTH_COMPONENT32:
       return &_mesa_texformat_z16;
 
+   case GL_DEPTH_STENCIL_EXT:
+   case GL_DEPTH24_STENCIL8_EXT:
+      return &_mesa_texformat_z24_s8;
+
    default:
       fprintf(stderr, "unexpected texture format %s in %s\n",
               _mesa_lookup_enum_by_nr(internalFormat), __FUNCTION__);