Adds a reference to a symbol; unknown symbols are marked as unresolved
@param name
@param loc
function(name, loc) {
      var str = "";
      for (var i = 0; i < name.length; i++) {
        if (i) {
          str += ".";
        }
        str += name[i];
        if (qx.tool.compiler.ClassFile.GLOBAL_SYMBOLS[str] || this.isIgnored(str)) {
          return;
        }
      }
      name = name.join(".");
      if (name == this.__className || name.startsWith(this.__className + ".") || name.startsWith("(")) {
        return;
      }
      if (name == "qx.ui.tooltip.ToolTip")
        debugger;
      var scope = this.__scope;
      if (scope.vars[name] !== undefined) {
        return; 
      }

      if (!scope.unresolved[name]) {
        scope.unresolved[name] = {
          name: name,
          locations: loc ? [loc] : [],
          load: this.isLoadScope(),
          defer: this.__inDefer
        }; 
      } else if (loc) {
        scope.unresolved[name].locations.push(loc);
      }
    }