I have resequenced the above post to make the answers
It's an open-source project, so he'll be offering the results to anyone who wants it.
If I give away my books, does that make it ethical that I plagiate someone elses book?

He's trying to lead a collaborative project, and is looking for people who can contribute specific information about specific tools.
He's not trying to circumvent anything, or rip-off anyone.
I don't see anything underhand, or illegitimate about it.
What if I were "looking for people who can contribute specific information about" my competitors products where is the difference between that and the above?

Seems a very worthy scheme to me.
The scheme may be worthy, but obtaining information by false pretenses can never be ethically correct. (yes, "he" does not post "false pretenses" but those that obtained the information did not state "to give to SDCC", thus the falsehood exist).
One example, while not a compiler is the FREE SILabs software where the 'conditions' state "may not be distributed" and on a question in the SILabs forum the answer was "NO you may NOT distribute it, but ANYONE may download it from our site." This seems to indicate that the "free" software is free to "known" recipients.

Erik

PS I think SDCC has a purpose, and this is not a tirade against SDCC as such I agree tthat SDCC per se is "a very worthy scheme". It is just that sometimes you see the "when we give it away we are free to take" attitude which makes the hair in my neck stand straight up.

The Open source/free software movement, I am sure has a purpose, but copyright infringement is still copyright infringement regardless of whether you yourself claim copyright.