devel/py-wheel: Fix extraction when cross-building the port

Override EXTRACT_CMD and pass the variable LC_ALL to fix the extraction
of the distfile.
The build fails when cross-building the port with the following error:

> SHA256 Checksum OK for wheel-0.38.4.tar.gz.

tar: Pathname can't be converted from UTF-8 to current locale.
tar: Error exit delayed from previous errors.

PR: 268500
Reported by: <bas@area536.com>