message: Fix Metal unused variable warning
diff: @@ -91,12 +91,14 @@ blitterFrag(VertexOut in [[stage_in]],
  {
  FragmentOut out = {};
  +#if defined(BLIT_COLOR) || defined(BLIT_DEPTH)
  // These coordinates match the Vulkan vkCmdBlitImage spec:
  // https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/vkCmdBlitImage.html
  float2 uvbase = in.position.xy; // unnormalized coordinates at center of texel: (1.5, 2.5, etc)
  float2 uvoffset = uvbase - args->dstOffset;
  float2 uvscaled = uvoffset * args->scale;
  float2 uv = uvscaled + args->srcOffset;
  +#endif
  #ifdef BLIT_COLOR
  #ifdef MSAA_COLOR_SOURCE
  