Log Message:
x11/tk: Upgrade from version 8.4.18 to 8.5.12

Highlights of Tk 8.5
  * New modern theming engine: New and complementary widgets that make use
    of platform-specific theming on Mac OS X and Windows to better fit in
    with those environments, and feature an improved look and feel under
    X11.
  * New widgets: Part of the themed widget set, Tk now has core notebook,
    combobox, treeview and progressbar widgets.
  * text widget: Smooth scrolling, widget peering, and improved procedures
    for counting and replacing text.
  * Font rendering: Now uses anti-aliased text under X11, and a more
    modern text engine (ATSUI) on Mac OS X.
  * Additional improvements: Window transparency, new fullscreen option
    for windows, enhancements to specific widgets and window layout,
    and more.

There is of course much, much more.
See [8.5 Changes](http://wiki.tcl.tk/10630) on the wiki for a complete
list of new features.