COMP: adjustments for nvc++ compiler

- remove unneeded -Wno-old-style flags with boost/cgal elements
- add nvc equivalent to gcc/clang -Wno-invalid-offsetof
- avoid warnings about set-but-unused variable and change of scoping

STYLE: remove wmake 'CGAL' rule
- was a transitional forward to 'cgal' rule since DEC-2020

applications/utilities/mesh/generation/foamyMesh/foamyHexMeshSurfaceSimplify/Make/options

@@ -4,7 +4,6 @@ include $(GENERAL_RULES)/cgal
 
 EXE_INC = \
     -DUNIX \
-    -Wno-old-style-cast \
     /* -IMarchingCubes */ \
     -I$(FASTDUALOCTREE_SRC_PATH) \
     -I../conformalVoronoiMesh/lnInclude \

applications/utilities/preProcessing/viewFactorsGen/Make/options

@@ -1,7 +1,6 @@
 include $(GENERAL_RULES)/cgal-header-only
 
 EXE_INC = \
-    -Wno-old-style-cast \
     $(COMP_FLAGS) \
     ${CGAL_INC} \
     -I$(LIB_SRC)/finiteVolume/lnInclude \
@@ -9,7 +8,6 @@ EXE_INC = \
     -I$(LIB_SRC)/meshTools/lnInclude \
     -I$(LIB_SRC)/parallel/distributed/lnInclude
 
-
 EXE_LIBS = \
     -lfiniteVolume \
     -lsurfMesh \

applications/utilities/surface/surfaceBooleanFeatures/PolyhedronReader/Make/options

@@ -1,8 +1,6 @@
 EXE_NDEBUG = -DNDEBUG
 /* EXE_NDEBUG = -g -O0 -DFULLDEBUG */
 
-c++CGALWARN = -Wno-old-style-cast
-
 /*-- Define CGAL_INEXACT to use inexact CGAL constructions */
 
 include $(GENERAL_RULES)/cgal
@@ -11,7 +9,6 @@ EXE_INC = \
     ${ROUNDING_MATH} \
     ${EXE_NDEBUG} \
     ${CGAL_INC} \
-    ${c++LESSWARN} \
     -I.. \
     -I$(LIB_SRC)/surfMesh/lnInclude \
     -I$(LIB_SRC)/meshTools/lnInclude