message: Force sRGB rendering in multithreaded test
diff: @@ -90,7 +90,7 @@ void main()
  A.tex = MakeTexture();
  glBindTexture(GL_TEXTURE_2D, A.tex);
  - glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, screenWidth, screenHeight);
  + glTexStorage2D(GL_TEXTURE_2D, 1, GL_SRGB8_ALPHA8, screenWidth, screenHeight);
  B.VB = MakeBuffer();
  glBindBuffer(GL_ARRAY_BUFFER, B.VB);
  @@ -100,7 +100,7 @@ void main()
  B.tex = MakeTexture();
  glBindTexture(GL_TEXTURE_2D, B.tex);
  - glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, screenWidth, screenHeight);
  + glTexStorage2D(GL_TEXTURE_2D, 1, GL_SRGB8_ALPHA8, screenWidth, screenHeight);
  // make FBOs on the main context for reading
  GLuint Afbo = MakeFBO();
  @@ -130,6 +130,8 @@ void main()
  ActivateContext(ctx.win, ctx.ctx);
  + glEnable(GL_FRAMEBUFFER_SRGB);
  +
  glGenVertexArrays(1, &ctx.VAO);
  glBindVertexArray(ctx.VAO);
  