check that core was compiled without mpi

config/sst_check_ariel_mpi.m4

@@ -8,7 +8,9 @@ AC_DEFUN([SST_CHECK_ARIEL_MPI], [
   AS_IF([test "$enable_ariel_mpi" = "yes"], [sst_check_ariel_mpi_happy="yes"])
 
   dnl Ensure Core was compiled without MPI
-  dnl TODO: Remove this requirement in a future release
+  dnl Regrettably, this runs before we have checked whether sst-config exists,
+  dnl as that config file overwrites the MPICXX and MPICC variables needed by
+  dnl the ACX_MPI macro. We plan to remove this check altogether in the future.
   AC_MSG_CHECKING([whether sst-core was compilied without MPI])
   sst_config_out=$(sst-config --MPI_CPPFLAGS)
   if test -z "$sst_config_out"; then

configure.ac

@@ -21,7 +21,6 @@ m4_include([config/sst_elements_include.m4])
 
 AM_PROG_AS
 
-SST_CHECK_ARIEL_MPI([], [AC_MSG_ERROR([Can't enable Ariel MPI])])
 AC_PROG_CC
 AM_PROG_CC_C_O
 m4_if(m4_defn([AC_AUTOCONF_VERSION]), 2.71,, m4_defn([AC_AUTOCONF_VERSION]), 2.70,, [AC_PROG_CC_C99])
@@ -42,11 +41,12 @@ LTDL_INIT([recursive])
 
 AC_CACHE_SAVE
 
+SST_CHECK_ARIEL_MPI([], [AC_MSG_ERROR([Can't enable Ariel MPI])])
+
 SST_CORE_CHECK_INSTALL()
 
 SST_CHECK_OSX()
 
-
 SST_CHECK_SPINLOCK()
 
 SST_ELEMENT_CONFIG_OUTPUT()