bibata-cursors: fix installation, don't generate unused w32 artifacts

This fixes issue where each theme installed the entire
build directory, not just the final generated 'out/X11' files.

(which was wasteful but also meant they didn't work
as the right files were two directories deeper)

Avoiding the w32 saves some time and sapce,
and more is "saved" by not shipping non-cursor build intermediates.

Sorry for the bad update, folks!

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

@@ -16,6 +16,11 @@ in stdenvNoCC.mkDerivation rec {
   postPatch = ''
     patchShebangs .
     substituteInPlace build.sh --replace "sudo" ""
+
+    # Don't generate windows cursors,
+    # they aren't used and aren't installed
+    # by the project's install script anyway.
+    echo "exit 0" > w32-make.sh
   '';
 
   nativeBuildInputs  = [
@@ -31,7 +36,9 @@ in stdenvNoCC.mkDerivation rec {
 
   installPhase = ''
     install -dm 0755 $out/share/icons
-    cp -pr Bibata_* $out/share/icons/
+    for x in Bibata_*; do
+      cp -pr $x/out/X11/$x $out/share/icons/
+    done
   '';
 
   meta = with stdenvNoCC.lib; {