rpm-sequoia: fixup darwin build

When building derivations that depends on rpm on darwin, we get the
following error:
```
dyld[69225]: Library not loaded: /nix/store/cz9sppfrs9ag34lq2pq6wmhspwcnvbxq-rpm-sequoia-1.7.0/lib/librpm_sequoia.1.7.0.dylib
  Referenced from: <0EA94AC5-F54A-3791-9374-4092232F33A1> /nix/store/mak6qp2pvgz19dn0fb0pr2lksgca43qp-rpm-4.20.0/lib/librpmio.10.2.0.dylib
  Reason: tried: '/nix/store/cz9sppfrs9ag34lq2pq6wmhspwcnvbxq-rpm-sequoia-1.7.0/lib/librpm_sequoia.1.7.0.dylib' (no such file), '/System/Vol>
cpio: premature end of archive
```

This commit adds the correct symlinks on darwin.

pkgs/by-name/rp/rpm-sequoia/package.nix

@@ -55,13 +55,17 @@ rustPlatform.buildRustPackage rec {
     ''
     +
       # Dependents will rely on the versioned symlinks
-      ''
+      lib.optionalString (!stdenv.hostPlatform.isDarwin) ''
         install -d $out/lib
         find target/release/ \
           -maxdepth 1 \
           -type l -name 'librpm_sequoia.*' \
           -exec cp --no-dereference {} $out/lib/ \;
-      '';
+      ''
+    + lib.optionalString stdenv.hostPlatform.isDarwin ''
+      install -d $out/lib
+      ln -s librpm_sequoia.dylib $out/lib/librpm_sequoia.${version}.dylib
+    '';
 
   passthru.updateScript = nix-update-script { };