[patch] fix recent bootstrap breakage on darwin

[Paolo Bonzini]

> How about committing the partial fix as is (including Andreas'
> snippet) to get darwin bootstrap going again and implementing this as
> an afterthought? There seems to be no obvious problem with omitting
> the two functions for now (meaning that the problem lies deeper and is
> more nasty)?

No, there is no obvious problem indeed, but it's a matter of cleanness.

Since darwin-f.c is totally trivial, go ahead even though I cannot 
approve it -- fix its comment as indicated by Steven, and commit to 
unbreak bootstrap.  Also make sure you consider the changes that Andreas 
needed.

Still, I'd appreciate that you commit (as much as that is possible in a 
free software project) to fix the issue properly soonish.

Paolo