glibc install problem caused by bug in zic (fwd)

[Olson, Arthur David (NCI)]

> ...
> 	(B)
> 	A bug in zic when creating a link but fromfile doesn't exist. The
> 	logic to build a relative path for symlink is just plain wrong.
> >How-To-Repeat:
> ...
> 	(B)
> 	Run "zic -d `pwd`/zone test" with an input file `test'
> 	containing just one line: "Link Some/Where Bad/Link"
> ...
>  }
> ...
> +		        /*
> +		        ** Proceed if there is a common prefix,
> +		        ** otherwise we can't create a reasonable symlink
> +		        ** (only happens when input and -d option are weird)
> +		        */

I can see how it's desirable to add a check that the fromfile exists when
processing a "Link" line
and resorting to a symbolic link. I don't (yet) see the need for a common
prefix; I'd love it if someone could enlighten me.

				--ado