Change the return value when BezierNom is called along a nonmanifold …

…edge with 2 singular extremities.

If we return 1. The point is inserted along the nom edge but its normals have not been computed (so they can be NaN).

src/mmg3d/tools_3d.c

@@ -595,7 +595,9 @@ inline int MMG5_BezierNom(MMG5_pMesh mesh,MMG5_int ip0,MMG5_int ip1,double s,dou
     /* Coordinates of the new tangent and normal */
     if ( MG_SIN(p0->tag) && MG_SIN(p1->tag) ) {  // function should not be used in that case
         memcpy(to,t0,3*sizeof(double));
-        return 1;
+        /* returning 1 here may create memory error afterward because no (that
+         * is not filled) will be used */
+        return 0;
     }
     else if ( MG_SIN(p0->tag) ) {
         memcpy(n1,&(mesh->xpoint[p1->xp].n1[0]),3*sizeof(double));