tuxpaint: move icon to spec-compliant location

pkgs/by-name/tu/tuxpaint/package.nix

@@ -91,7 +91,6 @@ stdenv.mkDerivation (finalAttrs: {
   postInstall = ''
     # Install desktop file
     mkdir -p $out/share/applications
-    cp hildon/tuxpaint.xpm $out/share/pixmaps
     sed -e "s+Exec=tuxpaint+Exec=$out/bin/tuxpaint+" < src/tuxpaint.desktop > $out/share/applications/tuxpaint.desktop
 
     # Install stamps
@@ -99,6 +98,10 @@ stdenv.mkDerivation (finalAttrs: {
     cd tuxpaint-stamps-*
     make install-all PREFIX=$out
 
+    mkdir -p $out/share/icons/hicolor/32x32/apps
+    magick $out/share/pixmaps/tuxpaint.png -resize 32x32 $out/share/icons/hicolor/32x32/apps/tuxpaint.png
+    rm -r $out/share/pixmaps
+
     # Requirements for tuxpaint-import
     wrapProgram $out/bin/tuxpaint-import \
       --prefix PATH : ${lib.makeBinPath [ netpbm ]}