COMP: forward declarations to silence gcc-7 warnings about 'operator<<'

meshLibrary/utilities/anisotropicMeshing/coordinateModification/boxScaling.H

@@ -46,6 +46,10 @@ namespace Foam
 namespace Module
 {
 
+// Forward declarations
+class boxScaling;
+Ostream& operator<<(Ostream&, const boxScaling&);
+
 /*---------------------------------------------------------------------------*\
                          Class boxScaling Declaration
 \*---------------------------------------------------------------------------*/

meshLibrary/utilities/containers/VRWGraph/VRWGraph.H

@@ -51,7 +51,9 @@ namespace Foam
 namespace Module
 {
 
+// Forward declarations
 class VRWGraph;
+Ostream& operator<<(Ostream&, const VRWGraph&);
 
 class rowElement
 {

meshLibrary/utilities/containers/VRWGraphList/VRWGraphList.H

@@ -47,6 +47,10 @@ namespace Foam
 namespace Module
 {
 
+// Forward declarations
+class VRWGraphList;
+Ostream& operator<<(Ostream&, const VRWGraphList&);
+
 /*---------------------------------------------------------------------------*\
                         Class VRWGraphList Declaration
 \*---------------------------------------------------------------------------*/