The Windows 64-bit ABI, for starters. The world is not Unix. As for additional text: compare that with the code spent on explicit checks of error values. You can't just enable exceptions on an existing codebase and point to how awful they are without account for the now-extraneous code that exception support allows you to remove.
the x86_64 psabi also requires eh_frame but it's actually not used for much except exceptions, stack unwinding, etc thus is mostly useless. Of course all of this is sort of moot with rust as rust requires eh_frame.. and the resulting bloat.
