make blue background not the default behavior even in DEBUG builds

Author: sh95014

source/frontends/mariani/EmulatorViewController.mm

@@ -133,7 +133,7 @@ - (void)rebuildView:(BOOL)notify {
     _view.enableSetNeedsDisplay = NO;
     _view.device = MTLCreateSystemDefaultDevice();
     _view.numericKeyDelegate = self;
-#ifdef DEBUG
+#ifdef DEBUG_BLUE_BACKGROUND
     //  useful for debugging quad sizing issues.
     _view.clearColor = MTLClearColorMake(0.0, 0.15, 0.3, 0.3);
 #endif