diff --git a/src/Mod/CAM/App/PathSegmentWalker.cpp b/src/Mod/CAM/App/PathSegmentWalker.cpp
index b87aa34bbd..93718ae39c 100644
--- a/src/Mod/CAM/App/PathSegmentWalker.cpp
+++ b/src/Mod/CAM/App/PathSegmentWalker.cpp
@@ -32,7 +32,6 @@
 #define ARC_MIN_SEGMENTS   20.0  // minimum # segments to interpolate an arc
 
 #ifndef M_PI
-    #define M_PI 3.14159265358979323846
     #define M_PI    3.14159265358979323846 /* pi */
 #endif