mpi_f08: restore C/Fortran compatibility with F08 BUFFER_DETACH

The C int/Fint interoperability code was erroneously removed when this
function was moved to the use-mpi-f08 directory.

ompi/mpi/fortran/use-mpi-f08/buffer_detach.c

@@ -53,13 +53,15 @@ void ompi_buffer_detach_f08(char *buffer, MPI_Fint *size, MPI_Fint *ierr)
 {
     int c_ierr;
     void *dummy;
+    OMPI_SINGLE_NAME_DECL(size);
 
-    c_ierr = MPI_Buffer_detach(&dummy, size);
+    c_ierr = MPI_Buffer_detach(&dummy, OMPI_SINGLE_NAME_CONVERT(size));
     if (NULL != ierr) {
         *ierr = OMPI_INT_2_FINT(c_ierr);
     }
 
     if (MPI_SUCCESS == c_ierr) {
+        OMPI_SINGLE_INT_2_FINT(size);
         *(void **)buffer = dummy;
     }
 }