tinyexr: Enable C++11 threaded loading
tinyexr: Enable C++11 threaded loading

(cherry picked from commit 2175397210b5e433e3cb63d1aad4a9d6e53aabec)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot