Qt map column 0

Column 0 ought to be suppressed like it is for tty and curses (not
sure about X11 or Windows GUI), but until that happens, display it as
'nothing'.  The glyph overhaul not too long ago resulted in it being
shown as a column of giant ants.

We ought to have some special 'none of the above' tile #0 that will
stand out enough to be reported and fixed.  Glyph #0 too.

win/Qt/qt_map.cpp

@@ -6,6 +6,8 @@
 
 extern "C" {
 #include "hack.h"
+
+extern glyph_map glyphmap[MAX_GLYPH]; /* from tile.c */
 }
 
 #include "qt_pre.h"
@@ -500,14 +502,14 @@ void NetHackQtMapViewport::Clear()
         Glyphttychar(0, j) = ' ';
         Glyphcolor(0, j) = NO_COLOR;
         Glyphflags(0, j) = 0U;
-        Glyphtileidx(0, j) = 0;
+        Glyphtileidx(0, j) = ::glyphmap[GLYPH_NOTHING].tileidx;
 
         for (int i = 1; i < COLNO; ++i) {
             Glyph(i, j) = GLYPH_UNEXPLORED;
             Glyphttychar(i, j) = ' ';
             Glyphcolor(i, j) = NO_COLOR;
             Glyphflags(i, j) = 0U;
-            Glyphtileidx(i, j) = 0;
+            Glyphtileidx(i, j) = ::glyphmap[GLYPH_UNEXPLORED].tileidx;
         }
     }