This directory shows how you can set up a Makefile so that the client
program will be remade when a new widget is put into the description
language.  Trivial changes to the description file will not force
recompilation or linking.

The essentials are that the client program includes a .wh file that
contains the required "make_tag_class_list()" function.  In this case,
xmake.c includes xmake.wh.  This include file only changes when a widget
is added to the description language that isn't found in the include file.

To test this yourself, notice that executing "make xmake" a second time
will result in no action since everything is up to date.  If you
"touch incl.wl", then "make xmake", a little something will happen,
but the client will not be remade since it was determined that nothing
significant changed, even though one of the description files was modified.
If you edit incl.wl to have an XcuCommand widget instead of an XcuLabel widget,
and then "make xmake", xmake will be completely remade.

At this point, "xmake.wh" will contain the XcuLabel widget, too, since
it accumulates all widgets ever mentioned.  To get a fresh, minimal file,
remove the files xmake.nc and xmake.wb before making again.
