Are you trying to build directly from the master branch or is this already the branch with your changes?
In the latter case, check your git diff as you seem to have changed the size of TensorImpl:
/home/khushi/anaconda3/lib/python3.8/site-packages/torch/include/c10/core/TensorImpl.h(2615): error: static assertion failed with "You changed the size of TensorImpl on 64-bit arch.See Note [TensorImpl size constraints] on how to proceed."

in the former case, which commits are you using?