I have successfully build pytorch. And the changes in python files are reflected instantly as I have build using
NO_CUDA=1 python3 setup.py develop

But, I am making changes in the cpp files and I am trying to build  it using this
python3 setup.py clean
NO_CUDA=1 python3 setup.py develop

and it failes with this error
subprocess.calledprocesserror: command '['ninja', 'install']' returned non-zero exit status 1.

Also, its taking about 20mins to reach to this point, any way of doing this faster? I just have to build the native files.