It has to be either 841ff8eb49 or 711ce27baf or both. I'm quite sure of that, since 9e53683ca0 and previous commits are not affected while a259025d31 and later are.
The commits between the two won't build and zlib was ruled out as a possible cause. So that leaves us with 841ff8eb49 and/or 711ce27baf as only possible brakers.
Sorry, I don't have a clue as to what "hacking out the mod's" even means. EDIT:
oh yeah, I do know what that means. It took me a while (I'm not a native English speaker)
Reading the code, the only thing that draw my attention was that both mmx as well as sse2 have vanished from configure.inc