Fixes GH-2941.

Closes GH-2976.

When passing keyword arguments from unpacked dict literals, prevent duplicate dict keys from raising an error and instead overwrite the previous one.
Closes GH-2963.

This was broken by the attempt to exclude C++ operations from true division.

Move the variable declarations in a C helper function to where they are actually used to avoid "unused" warnings in Py3.

This was broken by the attempt to exclude C++ operations from true division.

This fixes Github issue #1950.

This fixes Github issue #1950.

Fix compile error with 3.8

Replace optparse by argparse

Positional-only code generation optimization