Support installing headers for bootstrapping libgcc

[Nix]

On 11 May 2012, Roland McGrath stated:
> I think we can just get rid of sln entirely at this point.  We really
> don't expect anybody to be able to run 'make install' directly on a
> live system and not ruin all sorts of things that might be needed
> somewhere in the process.  So why should ln be different?

You might well break various glibc postinstall scripts if you do that.
(You'll certainly break mine, though I don't like sln(1) either.)

Of course fixing these scripts is trivial -- make the symlink before
moving things out of the installed DESTDIR -- but you probably want to
mention such a removal in NEWS before anyone fouls up their systems as a
result.

> That leaves only ldconfig, which is statically-linked for a much more
> defensible reason.

Yep.

-- 
NULL && (void)