Don't override SOURCE_CODE_URL in Default_Version.h
- 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”