Consistently include <math.h> with angle brackets

modules/calib3d/src/chessboard.cpp

@@ -5,7 +5,7 @@
 #include "precomp.hpp"
 #include "opencv2/flann.hpp"
 #include "chessboard.hpp"
-#include "math.h"
+#include <math.h>
 
 //#define CV_DETECTORS_CHESSBOARD_DEBUG
 #ifdef CV_DETECTORS_CHESSBOARD_DEBUG

modules/photo/src/npr.hpp

@@ -44,7 +44,7 @@
 #include <iostream>
 #include <stdlib.h>
 #include <limits>
-#include "math.h"
+#include <math.h>
 
 
 using namespace std;