fix macro USE_MPI and rename it to STARPU_USE_MPI

Makefile.am

@@ -35,7 +35,7 @@ endif
 
 SUBDIRS += doc
 
-if USE_MPI
+if STARPU_USE_MPI
 SUBDIRS += mpi
 endif
 

configure.ac

@@ -420,6 +420,7 @@ else
     cc_or_mpicc=$CC
 fi
 
+build_nmad_lib=no
 AC_SUBST(CC_OR_MPICC, $cc_or_mpicc)
 #We can only build StarPU MPI Library if User wants it and MPI is available
 if test x$use_mpi = xyes -a x$enable_nmad = xyes ; then
@@ -433,8 +434,6 @@ fi
 AC_MSG_CHECKING(whether the StarPU MPI nmad library should be generated)
 AC_MSG_RESULT($build_nmad_lib)
 
-AM_CONDITIONAL(USE_MPI, test "x$build_nmad_lib = xyes" -o "x$build_mpi_lib = xyes")
-
 ###############################################################################
 #                                                                             #
 #                                    DSM                                      #
@@ -607,7 +606,8 @@ else
 fi
 
 AM_CONDITIONAL(STARPU_USE_MPI_MPI, test x$build_mpi_lib = xyes)
-AM_CONDITIONAL(STARPU_USE_MPI_NMADI, test x$build_nmad_lib = xyes)
+AM_CONDITIONAL(STARPU_USE_MPI_NMAD, test x$build_nmad_lib = xyes)
+AM_CONDITIONAL(STARPU_USE_MPI, test x$build_nmad_lib = xyes -o x$build_mpi_lib = xyes)
 
 AC_ARG_WITH(mpiexec-args, [AS_HELP_STRING([--with-mpiexec-args[=<arguments to give when running mpiexec>]],
 			[Arguments for mpiexec])],

examples/stencil/Makefile.am

@@ -27,7 +27,7 @@ LIBS = $(top_builddir)/src/@LIBSTARPU_LINK@ $(HWLOC_LIBS) @LIBS@ $(FXT_LIBS)
 AM_CPPFLAGS = -I$(top_srcdir)/include/ -I$(top_srcdir)/examples/ -I$(top_builddir)/include
 AM_LDFLAGS = @STARPU_EXPORT_DYNAMIC@ $(STARPU_OPENCL_LDFLAGS) $(STARPU_CUDA_LDFLAGS) $(STARPU_COI_LDFLAGS) $(STARPU_SCIF_LDFLAGS)
 
-if USE_MPI
+if STARPU_USE_MPI
 LIBS += $(top_builddir)/mpi/src/libstarpumpi-@STARPU_EFFECTIVE_VERSION@.la
 AM_CPPFLAGS += -I$(top_srcdir)/mpi/include
 endif
@@ -64,7 +64,7 @@ check_PROGRAMS	=	$(LOADER) $(STARPU_EXAMPLES)
 endif
 
 if !STARPU_SIMGRID
-if USE_MPI
+if STARPU_USE_MPI
 if STARPU_MPI_CHECK
 TESTS		=	$(STARPU_EXAMPLES)
 endif