QtDialog: install the 128x128 icon

Also only install the icons to the icons directory.

Source/QtDialog/CMake.desktop

@@ -3,7 +3,7 @@ Version=1.0
 Name=CMake
 Comment=Cross-platform buildsystem
 Exec=cmake-gui %f
-Icon=CMakeSetup32
+Icon=CMakeSetup
 Terminal=false
 X-MultipleArgs=false
 Type=Application

Source/QtDialog/CMakeLists.txt

@@ -172,10 +172,16 @@ set(CMAKE_INSTALL_DESTINATION_ARGS
 install(TARGETS cmake-gui RUNTIME DESTINATION bin ${CMAKE_INSTALL_DESTINATION_ARGS})
 
 if(UNIX AND NOT APPLE)
+  foreach (size IN ITEMS 32 128)
+    install(
+      FILES       "${CMAKE_CURRENT_SOURCE_DIR}/CMakeSetup${size}.png"
+      DESTINATION "share/icons/hicolor/${size}x${size}/apps"
+      RENAME      "CMakeSetup.png")
+  endforeach ()
+
   # install a desktop file so CMake appears in the application start menu
   # with an icon
   install(FILES CMake.desktop DESTINATION share/applications )
-  install(FILES CMakeSetup32.png DESTINATION share/pixmaps )
   install(FILES cmakecache.xml DESTINATION share/mime/packages )
 endif()