bug#60875: Grafting breaks with clang-toolchain@13

[Leo Famulari]

On Tue, Jan 17, 2023 at 11:23:42AM +0100, Ludovic Courtès wrote:
> The file exists but it’s a dangling symlink:
> 
> --8<---------------cut here---------------start------------->8---
> $ ls -l 
> /gnu/store/12wnswvdc1mk9cr498dxflxim4qm2pyq-clang-toolchain-13.0.1/lib/libz.so.1.2.11
> lrwxrwxrwx 1 guixbuilder01 guixbuild 74 Jan 17 10:36 
> /gnu/store/12wnswvdc1mk9cr498dxflxim4qm2pyq-clang-toolchain-13.0.1/lib/libz.so.1.2.11
>  -> /gnu/store/v8d7j5i02nfz951x1szbl9xrd873vc3l-zlib-1.2.12/lib/libz.so.1.2.11
> $ stat -L 
> /gnu/store/12wnswvdc1mk9cr498dxflxim4qm2pyq-clang-toolchain-13.0.1/lib/libz.so.1.2.11
> stat: cannot statx 
> '/gnu/store/12wnswvdc1mk9cr498dxflxim4qm2pyq-clang-toolchain-13.0.1/lib/libz.so.1.2.11':
>  No such file or directory
> --8<---------------cut here---------------end--------------->8---

Merged with <https://issues.guix.gnu.org/issue/60584>