From the release notes:
>> The code has been updated to work with newer versions of the compiler
So.... GNU broke their compiler to the point that it wouldn't compile existing code; and then their other projects need to change their sources to work? Doesn't that seem horribly backwards?
Hurd is billed as being written in "assembly and C", but evidently it wasn't any sort of standardized assembly or C, it was some private variant that only GNU understood, and only GNU could compile. Now that GCC doesn't accept their non-standard code, they had to spend months rewriting everything in standardized form..... bizarre. Great use of the limited resources available.