Update PATH to include python_impl dependent script path

[pva]

Suggestion to fixes issue #12.

[pva]

Oh, BTW, probably we need to copy env_path to a temporary buffer, otherwise reset will not work. I'll fix this if you agree with a general idea of the patch.

[mgorny]

python-exec avoids allocating memory by design. Not to mention you don't even check for failed allocations, so you're introducing a vulnerability.

[pva]

python-exec avoids allocating memory by design. Not to mention you don't even check for failed allocations, so you're introducing a vulnerability.

Yea, I've noticed that there are no allocations but I wanted to check that with new path there will be no warning. It worked.

Do you have any idea on how to update env without allocating place to store updated PATH value? Static buffer? I failed to find size for such buffer. It looks like there is no limit on size for env variable value.