Update recastnavigation lib to 1.6

Source/ThirdParty/recastnavigation/RecastMesh.cpp

@@ -16,7 +16,6 @@
 // 3. This notice may not be removed or altered from any source distribution.
 //
 
-#define _USE_MATH_DEFINES
 #include <math.h>
 #include <string.h>
 #include <stdio.h>
@@ -35,7 +34,7 @@ static bool buildMeshAdjacency(unsigned short* polys, const int npolys,
 							   const int nverts, const int vertsPerPoly)
 {
 	// Based on code by Eric Lengyel from:
-	// http://www.terathon.com/code/edges.php
+	// https://web.archive.org/web/20080704083314/http://www.terathon.com/code/edges.php
 	
 	int maxEdgeCount = npolys*vertsPerPoly;
 	unsigned short* firstEdge = (unsigned short*)rcAlloc(sizeof(unsigned short)*(nverts + maxEdgeCount), RC_ALLOC_TEMP);
@@ -566,7 +565,6 @@ static bool canRemoveVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned sho
 	const int nvp = mesh.nvp;
 	
 	// Count number of polygons to remove.
-	int numRemovedVerts = 0;
 	int numTouchedVerts = 0;
 	int numRemainingEdges = 0;
 	for (int i = 0; i < mesh.npolys; ++i)
@@ -586,7 +584,6 @@ static bool canRemoveVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned sho
 		}
 		if (numRemoved)
 		{
-			numRemovedVerts += numRemoved;
 			numRemainingEdges += numVerts-(numRemoved+1);
 		}
 	}
@@ -989,7 +986,7 @@ static bool removeVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned short
 /// limit must be retricted to <= #DT_VERTS_PER_POLYGON.
 ///
 /// @see rcAllocPolyMesh, rcContourSet, rcPolyMesh, rcConfig
-bool rcBuildPolyMesh(rcContext* ctx, rcContourSet& cset, const int nvp, rcPolyMesh& mesh)
+bool rcBuildPolyMesh(rcContext* ctx, const rcContourSet& cset, const int nvp, rcPolyMesh& mesh)
 {
 	rcAssert(ctx);