ENH: scotchDecomp: add mpi compilation since scotch.h seems to include mpi.h

src/parallel/decompose/scotchDecomp/Make/options

+# Note including of mplib compilation rules. This
+# is purely to avoid scotch.h including mpicxx.h
+# which causes problems.
+sinclude $(GENERAL_RULES)/mplib$(WM_MPLIB)
+sinclude $(RULES)/mplib$(WM_MPLIB)
+
 EXE_INC = \
+    $(PFLAGS) $(PINC) \
     -I$(SCOTCH_ARCH_PATH)/include \
     -I/usr/include/scotch \
     -I../decompositionMethods/lnInclude