This is needed because the object is included by value in STL containers.

Change-Id: I4008aa3b733bdfc6c045a7622a0e40d7eb61b0bf
Reviewed-on: https://swiftshader-review.googlesource.com/3811Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>