MRENCLAVE not reproducible when building from source

[anirbanc3]

I am performing a study on reproducibility of TEE builds. I first tried to build the demo hello_world program inside the docker image as per the instructions given in https://github.com/google/asylo#build-environment-in-docker-recommended . Then, I followed the steps in https://github.com/google/asylo/blob/master/INSTALL.md to buld Asylo from source and run the same hello_world program using the newly build Asylo. The MRENCLAVE of the hello_world program differs in the two cases. I was wondering what could be the reason that the enclave hashes are different and if there is any additional steps that I missed.