message: ensure that MPI libs are build in time
diff: .PRECIOUS: bin/stanc$(EXE)
  -bin/stanc$(EXE) : bin/cmdstan/stanc.o bin/libstanc.a
  +bin/stanc$(EXE) : bin/cmdstan/stanc.o bin/libstanc.a $(LIBMPI)
  @mkdir -p $(dir $@)
  $(LINK.cc) -O$(O_STANC) $(OUTPUT_OPTION) $< $(LDLIBS_STANC)
  .PRECIOUS: bin/print$(EXE)
  -bin/print$(EXE) : bin/cmdstan/print.o
  +bin/print$(EXE) : bin/cmdstan/print.o $(LIBMPI)
  @mkdir -p $(dir $@)
  $(LINK.cc) -O$(O_STANC) $(OUTPUT_OPTION) $<
  .PRECIOUS: bin/stansummary$(EXE)
  -bin/stansummary$(EXE) : bin/cmdstan/stansummary.o
  +bin/stansummary$(EXE) : bin/cmdstan/stansummary.o $(LIBMPI)
  @mkdir -p $(dir $@)
  $(LINK.cc) -O$(O_STANC) $(OUTPUT_OPTION) $<
  .PRECIOUS: bin/diagnose$(EXE)
  -bin/diagnose$(EXE) : bin/cmdstan/diagnose.o
  +bin/diagnose$(EXE) : bin/cmdstan/diagnose.o $(LIBMPI)
  @mkdir -p $(dir $@)
  $(LINK.cc) -O$(O_STANC) $(OUTPUT_OPTION) $<
  