Fix -Wincompatible-pointer-types warning from gcc
    
    chooser.c:280:26: warning: passing argument 2 of ‘XawListChange’ from
     incompatible pointer type [-Wincompatible-pointer-types]
      280 |     XawListChange (list, newTable, size, 0, TRUE);
          |                          ^~~~~~~~
          |                          |
          |                          char **
    In file included from chooser.c:59:
    /usr/include/X11/Xaw/List.h:170:27: note: expected ‘const char **’ but
     argument is of type ‘char **’
      170 |  _Xconst char           **list,
    
    Copied from XDM patch