Updated warning options for GCC; fixed new warnings.

samples/c/morphology.c

@@ -17,6 +17,7 @@ int erode_dilate_pos = 0;
 // callback function for open/close trackbar
 static void OpenClose(int pos)
 {
+    (void)pos;
     int n = open_close_pos - max_iters;
     int an = n > 0 ? n : -n;
     element = cvCreateStructuringElementEx( an*2+1, an*2+1, an, an, element_shape, 0 );
@@ -37,6 +38,7 @@ static void OpenClose(int pos)
 // callback function for erode/dilate trackbar
 static void ErodeDilate(int pos)
 {
+    (void)pos;
     int n = erode_dilate_pos - max_iters;
     int an = n > 0 ? n : -n;
     element = cvCreateStructuringElementEx( an*2+1, an*2+1, an, an, element_shape, 0 );