Clean STM32 compile warnings

sw/airborne/subsystems/navigation/OSAMNav.c

@@ -128,6 +128,8 @@ bool_t FlowerNav(void)
 		}
 		break;
 
+	default:
+		break;
 	}
 	return TRUE;
 }
@@ -844,6 +846,8 @@ bool_t VerticalRaster(uint8_t l1, uint8_t l2, float radius, float AltSweep) {
       line_status = LR12;
       nav_init_stage();
     }
+  default:
+    break;
   }
   return TRUE; /* This pattern never ends */
 }

sw/airborne/subsystems/navigation/discsurvey.c

@@ -74,6 +74,8 @@ bool_t disc_survey( uint8_t center, float radius) {
       nav_init_stage();
     }
     break;
+  default:
+    break;
   }
 
   NavVerticalAutoThrottleMode(0.); /* No pitch */

sw/airborne/subsystems/navigation/poly_survey_adv.c

@@ -85,11 +85,11 @@ static void nav_points(point2d start, point2d end)
 **/
 static bool_t intercept_two_lines(point2d *p, point2d x, point2d y, float a1, float a2, float b1, float b2)
 {
-  float div, fac;
+  float divider, fac;
 
-  div = (((b2 - a2)*(y.x - x.x)) + ((x.y - y.y)*(b1 - a1)));
-  if (div == 0) return FALSE;
-  fac = ((y.x*(x.y - a2)) + (x.x*(a2 - y.y)) + (a1*(y.y - x.y))) / div;
+  divider = (((b2 - a2)*(y.x - x.x)) + ((x.y - y.y)*(b1 - a1)));
+  if (divider == 0) return FALSE;
+  fac = ((y.x*(x.y - a2)) + (x.x*(a2 - y.y)) + (a1*(y.y - x.y))) / divider;
   if (fac > 1.0) return FALSE;
   if (fac < 0.0) return FALSE;
 
@@ -164,7 +164,7 @@ bool_t init_poly_survey_adv(uint8_t first_wp, uint8_t size, float angle, float s
 {
   int i;
   point2d small, sweep;
-  float div, len, angle_rad = angle/180.0*M_PI;
+  float divider, len, angle_rad = angle/180.0*M_PI;
 
   if (angle < 0.0) angle += 360.0;
   if (angle >= 360.0) angle -= 360.0;
@@ -224,10 +224,10 @@ bool_t init_poly_survey_adv(uint8_t first_wp, uint8_t size, float angle, float s
   small.x = waypoints[poly_first].x;
   small.y = waypoints[poly_first].y;
 
-  div = (sweep_vec.y*dir_vec.x) - (sweep_vec.x*dir_vec.y);
+  divider = (sweep_vec.y*dir_vec.x) - (sweep_vec.x*dir_vec.y);
 
   //cacluate the leftmost point if one sees the dir vec as going "up" and the sweep vec as going right
-  if (div < 0.0) {
+  if (divider < 0.0) {
     for(i=1;i<poly_count;i++)
       if ((dir_vec.x*(waypoints[poly_first+i].y - small.y)) + (dir_vec.y*(small.x - waypoints[poly_first+i].x)) > 0.0) {
         small.x = waypoints[poly_first+i].x;

sw/airborne/subsystems/navigation/spiral.c

@@ -166,7 +166,8 @@ bool_t SpiralNav(void)
 	  }
 	  CSpiralStatus = Circle;
 	  break;
-
+       default:
+         break;
 	}
   return TRUE;
 }