Add a index for the f2c translation.

This commit was SVN r1273.

src/datatype/datatype.h

@@ -64,6 +64,7 @@ typedef struct ompi_datatype_t {
 
    /* Attribute fields */
    ompi_hash_table_t *d_keyhash;
+   int d_f_to_c_index;
    char name[MPI_MAX_OBJECT_NAME];
    dt_type_desc_t desc;     /**< the data description */
    dt_type_desc_t opt_desc; /**< short description of the data used when conversion is useless