* qt: move licence acceptance from qt3krell.patch to qt3accept.patch

* qt: ensure that ptrdiff_t is defined for qt@3.3.8b

* qt: disable webglplugin for qt@5.10~opengl

* qt: depend on libxext (for qt@3 and @4)

* qt: avoid X dependencies on darwin platforms

* Revert "qt: avoid X dependencies on darwin platforms"

This reverts commit 05ce08de94be1e02d7e2f2dae0c1ae59baa3f65a.

* qt: limit range of versions depending on libxext