[PATCH] Driver: implement --runtime-sysroot option.

[Rafael Espíndola]

>> If those don't work, I think my only remaining objection to this patch
>> is the option name sounds a bit too generic. What about dyld-path or
>> even sanitazer-libc-path?
>
> I chose that name because the runtime sysroot could in principle affect
> things other than the dynamic loader path, although I admittedly
> can't think of a good example of something else it ought to affect.
> --dyld-prefix sounds good to me since it's evident that it isn't the
> entire path to the loader.

--dyld-prefix is probably a good name.

Cheers,
Rafael