Hmm. Well, I was assuming that glibc was following the spec all along but just changed some implementation detail that mattered because Adobe wasn't following the spec all along.

I think there's an argument to be made that the way an API is implemented is an implicit contract that ought to be upheld. But that's not the arugment I see being made.

Anyway, this level of detail is below the scope of the "specs vs pragmatism" debate that's going on.