You could fix it by putting Python package files into proj/ directory:
proj/
src/
proj/
__init__.py
xyz.py
abc.py
setup.py
And changing setup.py to:
# ...
setup(
name="proj",
packages=['proj'],
package_dir={'':'src'}
)
It is not required by distutils but other tools might expect the parent directory name of __init__.py file to be the same as Python package name i.e., proj in this case.