All files used in myxlib fall under the Gnu copyleft except:
 Tree.c, TreeP.h, Tree.h, TMprint.c : These are adapted versions of files from
                                      the X distribution
 Canvas.c, CanvasP.h, Canvas.h      : These are adapted versions of files from
                                      the FWF (Free Widget Foundation)
 Several of the X files duplicate parts of functions found in the MIT X
 distribution (mainly: the colorconverter, MyNameToWidget, vararg to NestedList
 functions, PopupMenu function)