use mpiexec when lauching tools in master-slave mode

tools/Makefile.am

@@ -191,11 +191,19 @@ LOADER			=
 LOADER_BIN		=	$(top_builddir)/tests/loader-cross.sh
 endif
 
+if STARPU_USE_MPI_MASTER_SLAVE 
+MPI		= $(MPIEXEC)  $(MPIEXEC_ARGS) -np 4
+LOADER_BIN2	= $(MPI) $(LOADER_BIN)
+else
+LOADER_BIN2	= $(LOADER_BIN)
+endif
+
+
 if STARPU_HAVE_AM111
 TESTS_ENVIRONMENT	=	top_builddir="$(abs_top_builddir)" top_srcdir="$(abs_top_srcdir)"
-LOG_COMPILER		=	$(LOADER_BIN)
+LOG_COMPILER		=	$(LOADER_BIN2)
 else
-TESTS_ENVIRONMENT	=	top_builddir="$(abs_top_builddir)" top_srcdir="$(abs_top_srcdir)" $(LOADER_BIN)
+TESTS_ENVIRONMENT	=	top_builddir="$(abs_top_builddir)" top_srcdir="$(abs_top_srcdir)" $(LOADER_BIN2)
 endif
 
 endif