Fix missing glyph handling in modified stb_truetype.h (ttf branch)

stb_truetype.h

@@ -2330,7 +2330,7 @@ int stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc, stbtt_fontinfo *inf
             rects[k].w = (stbrp_coord) (x1-x0 + spc->padding + spc->h_oversample-1);
             rects[k].h = (stbrp_coord) (y1-y0 + spc->padding + spc->v_oversample-1);
 		 } else {
-            rects[k].w = rects[k].h = 0;
+            rects[k].w = rects[k].h = 1;
          }
 		 ++k;
       }