--- /dev/null
+--- opencv-3.1.0/opencv_contrib-3.1.0/modules/tracking/include/opencv2/tracking/onlineMIL.hpp~ 2015-12-17 18:11:31.000000000 +0100
++++ opencv-3.1.0/opencv_contrib-3.1.0/modules/tracking/include/opencv2/tracking/onlineMIL.hpp 2017-12-13 08:59:51.077710225 +0100
+@@ -54,8 +54,6 @@
+ //TODO based on the original implementation
+ //http://vision.ucsd.edu/~bbabenko/project_miltrack.shtml
+
+-#define sign(s) ((s > 0 ) ? 1 : ((s<0) ? -1 : 0))
+-
+ class ClfOnlineStump;
+
+ class CV_EXPORTS ClfMilBoost
+--- opencv-3.1.0/opencv_contrib-3.1.0/modules/tracking/src/onlineMIL.cpp~ 2015-12-17 18:11:31.000000000 +0100
++++ opencv-3.1.0/opencv_contrib-3.1.0/modules/tracking/src/onlineMIL.cpp 2017-12-13 09:00:15.158067835 +0100
+@@ -42,6 +42,8 @@
+ #include "precomp.hpp"
+ #include "opencv2/tracking/onlineMIL.hpp"
+
++#define sign(s) ((s > 0 ) ? 1 : ((s<0) ? -1 : 0))
++
+ template<class T> class SortableElementRev
+ {
+ public: