depends: Add native_qt package

Unlike Qt 5, Qt 6 requires a separate native Qt build for
cross-building.

See: https://www.qt.io/blog/qt-6-build-system.

depends/packages/packages.mk

@@ -11,6 +11,9 @@ qrencode_mingw32_packages = qrencode
 qt_linux_packages:=qt expat libxcb xcb_proto libXau xproto freetype fontconfig libxkbcommon libxcb_util libxcb_util_cursor libxcb_util_render libxcb_util_keysyms libxcb_util_image libxcb_util_wm
 qt_darwin_packages=qt
 qt_mingw32_packages=qt
+ifneq ($(host),$(build))
+qt_native_packages := native_qt
+endif
 
 bdb_packages=bdb
 sqlite_packages=sqlite