message: Add a fallback if TF varyings cause program not to link
diff: @@ -1128,6 +1128,16 @@ bool GLResourceManager::Serialise_InitialState(ResourceId resid, GLResource res)
  GLint status = 0;
  gl.glGetProgramiv(initProg, eGL_LINK_STATUS, &status);
  + // if it failed to link, first remove the varyings hack above as maybe the driver is barfing
  + // on trying to make some output a varying
  + if(status == 0)
  + {
  + gl.glTransformFeedbackVaryings(initProg, 0, NULL, eGL_INTERLEAVED_ATTRIBS);
  + gl.glLinkProgram(initProg);
  +
  + gl.glGetProgramiv(initProg, eGL_LINK_STATUS, &status);
  + }
  +
  // if it failed to link, try again as a separable program.
  // we can't do this by default because of the silly rules meaning
  // shaders need fixup to be separable-compatible.
  