[Bug target/55610] cc1 is calling munmap() on part of itself on darwin

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55610

--- Comment #8 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Iain Sandoe from comment #7)
> (In reply to Andrew Pinski from comment #6)
> > Does this work now?
> 
> It looks like Mike's suggestion works, but I don't recall seeing a patch -
> and the code for the unmap is present in trunk.  

maybe we can arrange for this block to be placed last in the address map (it
should be a .zerofill segment which are placed at the end anyway).  Not sure if
that would be enough to make dyld happy.