Overwriting existing PYTHONPATH

[aowenson-imm]

I am attempting to install your software into a cluster in a GNU environment module, loading other modules for its dependencies. But this line breaks that modularity:

physlr/bin/physlr-make

Line 41 in 4d32a99

python=env PYTHONPATH=$(physlr_path) $(python_executable)

Must it overwrite PYTHONPATH instead of prepending?