ENH: have ptscotch

ptscotch - compiles into ptscotchDecomp. All thirdparty decompositionMethods
now moved out of decompositionMethods so add them explicitly to link line
for programs that need them (decomposePar, snappyHexMesh etc.)

applications/utilities/mesh/generation/snappyHexMesh/Make/options

@@ -11,6 +11,7 @@ EXE_INC = \
 EXE_LIBS = \
     -lfiniteVolume \
     -ldecompositionMethods \
+    -L$(FOAM_MPI_LIBBIN) -lptscotchDecomp -lparMetisDecomp -lmetisDecomp \
     -lmeshTools \
     -ldynamicMesh \
     -lautoMesh

applications/utilities/mesh/generation/snappyHexMesh/snappyHexMesh.C

@@ -347,7 +347,7 @@ int main(int argc, char *argv[])
             << "You have selected decomposition method "
             << decomposer.typeName
             << " which is not parallel aware." << endl
-            << "Please select one that is (hierarchical, parMetis)"
+            << "Please select one that is (hierarchical, ptscotch, parMetis)"
             << exit(FatalError);
     }