config/ompi_ext: Don't include mpiext_*_mpifh.h in mpi_f08_ext

Including `mpiext_*_mpifh.h` in the source file of the `mpi_f08_ext`
module is not always appropriate. For example, if you want to define
a new datatype in an MPI extension, the `include 'mpif-ext.h'` binding
defines the datatype as `integer` but the `use mpi_f08_ext` binding
defines it as `type(mpi_datatype)`. They conflict.

This commit allows each MPI extension to declare whether it wants to
include its `mpiext_*_mpifh.h` in `mpi_f08` and `mpi_f08_ext`
respectively. The default (no declaration) is 'want'.

See `ompi/mpiext/example/configure.m4` for an example.

Signed-off-by: KAWASHIMA Takahiro <t-kawashima@jp.fujitsu.com>

Author: kawashima-fj

config/ompi_ext.m4

@@ -601,9 +601,15 @@ EOF
         #
         # Include the mpif.h header if it is available.  Cannot do
         # this from inside the usempi.h since, for VPATH builds, the
-        # srcdir is needed to find the header.
+        # srcdir is needed to find the header.  Each extension can
+        # refuse it by defining the OMPI_MPIEXT_$1_INCLUDE_MPIFH_IN_USEMPI
+        # macro in its ompi/mpiext/*/configure.m4.  See
+        # ompi/mpiext/example/configure.m4 for an example.
         #
-        if test "$enabled_mpifh" = 1; then
+        m4_ifdef([OMPI_MPIEXT_]$1[_INCLUDE_MPIFH_IN_USEMPI],
+                 [include_mpifh=OMPI_MPIEXT_$1_INCLUDE_MPIFH_IN_USEMPI],
+                 [include_mpifh=1])
+        if test "$enabled_mpifh" = 1 && test "$include_mpifh" != 0; then
             mpifh_component_header="mpiext_${component}_mpifh.h"
             cat >> $mpiusempi_ext_h <<EOF
 #include "${mpifh_component_header_path}"
@@ -657,9 +663,15 @@ EOF
         #
         # Include the mpif.h header if it is available.  Cannot do
         # this from inside the usempif08.h since, for VPATH builds,
-        # the srcdir is needed to find the header.
+        # the srcdir is needed to find the header.  Each extension can
+        # refuse it by defining the OMPI_MPIEXT_$1_INCLUDE_MPIFH_IN_USEMPIF08
+        # macro in its ompi/mpiext/*/configure.m4.  See
+        # ompi/mpiext/example/configure.m4 for an example.
         #
-        if test "$enabled_mpifh" = 1; then
+        m4_ifdef([OMPI_MPIEXT_]$1[_INCLUDE_MPIFH_IN_USEMPIF08],
+                 [include_mpifh=OMPI_MPIEXT_$1_INCLUDE_MPIFH_IN_USEMPIF08],
+                 [include_mpifh=1])
+        if test "$enabled_mpifh" = 1 && test "$include_mpifh" != 0; then
             mpifh_component_header="mpiext_${component}_mpifh.h"
             cat >> $mpiusempif08_ext_h <<EOF
 #include "${mpifh_component_header_path}"

ompi/mpiext/example/configure.m4

@@ -32,3 +32,11 @@ AC_DEFUN([OMPI_MPIEXT_example_CONFIG],[
 
 # only need to set this if the component needs init/finalize hooks
 AC_DEFUN([OMPI_MPIEXT_example_NEED_INIT], [1])
+
+# By default, mpiext_example_mpifh.h is included in the source file
+# of the mpi_ext module. To disable it, define this macro as 0.
+#AC_DEFUN([OMPI_MPIEXT_example_INCLUDE_MPIFH_IN_USEMPI], [0])
+
+# By default, mpiext_example_mpifh.h is included in the source file
+# of the mpi_f08_ext module. To disable it, define this macro as 0.
+#AC_DEFUN([OMPI_MPIEXT_example_INCLUDE_MPIFH_IN_USEMPIF08], [0])