> Allowing patches is necessary, but it's not sufficient. Debian's
> Free Software Guidelines has a similar clause, and I see no other
> clause that DJB's licence conflicts with. If I go by your statement,
> why is qmail listed under the non-free section?
Ability to distribute binaries built from modified source would seem
to be the key issue. From DFSG section 4:
The license must explicitly permit distribution of software
built from modified source code.
(As a note of personal preference, I think allowing "you can only
distribute the pristine source since patches" is a ridiculous
concession, and I don't consider software with such a license to be
"free" in the liberated sense at all. But my personal preference
isn't especially relevant to this discussion.)
