Do not fail the configure script if MPI_LAUNCH does not work and the mpirun...

Do not fail the configure script if MPI_LAUNCH does not work and the mpirun check is not requested explicitly.

configure.ac

@@ -41,13 +41,13 @@ AC_ARG_ENABLE([mpi],
 # for some systems (e.g. CRAY) mpirun/aprun check is not possible
 AC_ARG_ENABLE([mpirun-check],
               [AS_HELP_STRING([--disable-mpirun-check],
-                              [disable mpirun checks which might not work on some systems @<:@default: no@:>@])],
+                              [disable mpirun checks which might not work on some systems @<:@default: auto@:>@])],
               [case "${enableval}" in
                  yes) with_mpirun_check=true  ;;
                  no)  with_mpirun_check=false ;;
                  *) AC_MSG_ERROR([bad value ${enableval} for --disable-mpirun-check]) ;;
                esac],
-              [with_mpirun_check=true])
+              [with_mpirun_check=auto])
 
 # OpenMP
 AC_ARG_ENABLE([openmp],
@@ -64,7 +64,6 @@ AC_ARG_ENABLE([openmp],
 
 AM_CONDITIONAL([OPENMP],   [test x"$openmp" = xtrue])
 AM_CONDITIONAL([MPI],      [test x"$mpi"    = xtrue])
-AM_CONDITIONAL([MPICHECK], [test x"$with_mpirun_check" = xtrue])
 
 # DEBUG
 AC_ARG_ENABLE([debug],
@@ -179,7 +178,7 @@ AX_PROG_FC_MPI([test x"$mpi" != xfalse],
 
 AS_IF([test x"$mpi" != xfalse],
   # do not check for launch if mpirun-check is disabled
-  [AS_IF([test "x$with_mpirun_check" != "xtrue"],
+  [AS_IF([test "x$with_mpirun_check" = "xfalse"],
          [AC_MSG_WARN([check for MPI_LAUNCH disabled])],
          [AC_PATH_PROGS([MPI_LAUNCH], [poe mpirun mpiexec], [true])
        # set MP_HOSTFILE if we are using IBM PE
@@ -235,13 +234,17 @@ main(int argc, char **argv)
   return (procnum == cmdnum)?EXIT_SUCCESS:EXIT_FAILURE;
 }
 ])],
-                             [AS_IF([$MPI_LAUNCH -n 4 ./conftest$EXEEXT 4],
+                             [AS_IF([$MPI_LAUNCH -n 4 ./conftest$EXEEXT 4 >&AS_MESSAGE_LOG_FD 2>&1],
                                     [AC_MSG_RESULT([yes])],
                                     [AC_MSG_RESULT([no])
-                                     AC_MSG_FAILURE([$MPI_LAUNCH doesn't work])])],
+                                     AS_VAR_IF([with_mpirun_check], [auto],
+                                               [AC_MSG_WARN([$MPI_LAUNCH doesn't work])
+                                                with_mpirun_check=false],
+                                               [AC_MSG_FAILURE([$MPI_LAUNCH doesn't work])])])],
                              [AC_MSG_FAILURE([Cannot compile simple MPI program])])
              ])
 ])])
+AM_CONDITIONAL([MPICHECK], [test x"$with_mpirun_check" != xfalse])
 
 
 AC_FC_PP_SRCEXT([f90])