- Defining `SOURCE_CODE_URL` in `Default_Version.h` overrides it
elsewhere. So don’t define it there.
- Also fix up `language.h` so no `#undef` will be needed.

REVERT THIS CHANGE

In proper use, we want to force the vendor to update this file to reflect distribution parameters

However, until most users have converted to automatic versioning,
we “grant them a pass”