phinger-cursors: fix installPhase

Running `cp -r ./ $out/share/icons` to copy the icon files to
`$out/share/icons` ends up copying the `env-vars` file as well (since
sourceRoot = .), which can lead to collisions when building the system
path.

This uses a wildcard instead, which relies on the assumption that all
variants start with `phinger-cursors`.

pkgs/data/icons/phinger-cursors/default.nix

@@ -14,7 +14,7 @@ stdenvNoCC.mkDerivation rec {
   installPhase = ''
     runHook preInstall
     mkdir -p $out/share/icons
-    cp -r ./ $out/share/icons
+    cp -r ./phinger-cursors* $out/share/icons
     runHook postInstall
   '';