Fix -Wredundant-move warnings, 2nd try

std::move is redundant when it is used to return a local object from a function (eg return std::move(local)): indeed, returning a local object from a function implicitly moves it. Moreover using std::move this way
See https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rf-return-move-local
However, in order to avoid -Wreturn-std-move as well, a Base object is move-constructed
from Derived when required.

src/Mod/Part/App/FaceMakerCheese.cpp

@@ -236,7 +236,7 @@ TopoDS_Shape FaceMakerCheese::makeFace(const std::vector<TopoDS_Wire>& w)
                 builder.Add(comp, aFace);
         }
 
-        return std::move(comp);
+        return TopoDS_Shape(std::move(comp));
     }
     else {
         return TopoDS_Shape(); // error

src/Mod/Part/App/TopoShape.cpp

@@ -2222,7 +2222,7 @@ TopoDS_Shape TopoShape::makeHelix(Standard_Real pitch, Standard_Real height,
     TopoDS_Edge edgeOnSurf = BRepBuilderAPI_MakeEdge(segm , surf);
     TopoDS_Wire wire = BRepBuilderAPI_MakeWire(edgeOnSurf);
     BRepLib::BuildCurves3d(wire);
-    return std::move(wire);
+    return TopoDS_Shape(std::move(wire));
 }
 
 //***********
@@ -2308,7 +2308,7 @@ TopoDS_Shape TopoShape::makeLongHelix(Standard_Real pitch, Standard_Real height,
 
     TopoDS_Wire wire = mkWire.Wire();
     BRepLib::BuildCurves3d(wire);
-    return std::move(wire);
+    return TopoDS_Shape(std::move(wire));
 }
 
 TopoDS_Shape TopoShape::makeThread(Standard_Real pitch,
@@ -2926,9 +2926,10 @@ TopoDS_Shape TopoShape::makeOffset2D(double offset, short joinType, bool fill, b
         TopoDS_Compound result;
         BRep_Builder builder;
         builder.MakeCompound(result);
-        for(TopoDS_Shape &sh : shapesToReturn)
+        for(TopoDS_Shape &sh : shapesToReturn) {
             builder.Add(result, sh);
-        return std::move(result);
+        }
+        return TopoDS_Shape(std::move(result));
     }
     else {
         return shapesToReturn[0];
@@ -3175,7 +3176,7 @@ TopoDS_Shape TopoShape::removeSplitter() const
                 builder.Add(comp, xp.Current());
         }
 
-        return std::move(comp);
+        return TopoDS_Shape(std::move(comp));
     }
 
     return _Shape;

src/Mod/Part/Gui/DlgProjectionOnSurface.cpp

@@ -542,7 +542,7 @@ TopoDS_Shape PartGui::DlgProjectionOnSurface::create_compound(const std::vector<
       }
     }
   }
-  return std::move(aCompound);
+  return TopoDS_Shape(std::move(aCompound));
 }
 
 void PartGui::DlgProjectionOnSurface::show_projected_shapes(const std::vector<SShapeStore>& iShapeStoreVec)

src/Mod/Path/App/Area.cpp

@@ -1736,7 +1736,7 @@ TopoDS_Shape Area::toShape(CArea &area, short fill, int reorient) {
                 builder.Add(compound,s);\
             }\
             if(TopExp_Explorer(compound,TopAbs_EDGE).More())\
-                return std::move(compound);\
+                return TopoDS_Shape(std::move(compound));\
             return TopoDS_Shape();\
         }\
         return mySections[_index]->_op(_index, ## __VA_ARGS__);\
@@ -1873,8 +1873,9 @@ TopoDS_Shape Area::makeOffset(int index,PARAM_ARGS(PARAM_FARG,AREA_PARAMS_OFFSET
     }
     if(thicken)
         FC_DURATION_LOG(d,"Thicken");
-    if(TopExp_Explorer(compound,TopAbs_EDGE).More())
-        return std::move(compound);
+    if(TopExp_Explorer(compound,TopAbs_EDGE).More()) {
+        return TopoDS_Shape(std::move(compound));
+    }
     return TopoDS_Shape();
 }
 
@@ -2261,7 +2262,7 @@ TopoDS_Shape Area::toShape(const CArea &area, bool fill, const gp_Trsf *trsf, in
             AREA_WARN("FaceMakerBullseye failed: "<<e.what());
         }
     }
-    return std::move(compound);
+    return TopoDS_Shape(std::move(compound));
 }
 
 struct WireInfo {

src/Mod/Sketcher/App/ExternalGeometryExtension.cpp

@@ -66,14 +66,18 @@ void ExternalGeometryExtension::Restore(Base::XMLReader &reader)
 
 std::unique_ptr<Part::GeometryExtension> ExternalGeometryExtension::copy(void) const
 {
-    std::unique_ptr<ExternalGeometryExtension> cpy = std::make_unique<ExternalGeometryExtension>();
+    auto cpy = std::make_unique<ExternalGeometryExtension>();
 
     cpy->Ref = this->Ref;
     cpy->Flags = this->Flags;
 
     cpy->setName(this->getName()); // Base Class
 
+#if defined (__GNUC__) && (__GNUC__ <=4)
     return std::move(cpy);
+#else
+    return cpy;
+#endif
 }
 
 PyObject * ExternalGeometryExtension::getPyObject(void)

src/Mod/Sketcher/App/SketchGeometryExtension.cpp

@@ -75,13 +75,17 @@ void SketchGeometryExtension::Restore(Base::XMLReader &reader)
 
 std::unique_ptr<Part::GeometryExtension> SketchGeometryExtension::copy(void) const
 {
-    std::unique_ptr<SketchGeometryExtension> cpy = std::make_unique<SketchGeometryExtension>();
+    auto cpy = std::make_unique<SketchGeometryExtension>();
 
     cpy->Id = this->Id;
 
     cpy->setName(this->getName()); // Base Class
 
+#if defined (__GNUC__) && (__GNUC__ <=4)
     return std::move(cpy);
+#else
+    return cpy;
+#endif
 }
 
 PyObject * SketchGeometryExtension::getPyObject(void)