The Turkish club reportedly returned to the Scottish champions with an offer of £600,000 for the 26-year old wingback but McCoist says it does not bother him because the player is going nowhere.
"I don't even want to know what the new bid was. I am trying to build a squad here, not dismantle one," he told SunSport.
"Steven is a crucial part of that and I'm confident he will stay and we can clinch a new deal for him.
"Steven was superb for us last season, I have spoken with him and I feel his heart is here at Rangers."