* srfi-4.h, srfi-4.i.c (scm_u8vector_elements, etc): New.

* srfi-4.h, srfi-4.c (scm_uniform_vector_p,
scm_uniform_vector_ref, scm_uniform_vector_set_x,
scm_uniform_vector_to_list, scm_is_uniform_vector,
scm_c_uniform_vector_lengths, scm_c_uniform_vector_size,
scm_uniform_vector_elements, scm_uniform_vector_element_size,
scm_uniform_vector_release): New.
(scm_i_uniform_vector_prototype, scm_i_uniform_vector_tag): New.
(scm_uniform_element_size, scm_uniform_vector_length): Moved here
from unif.h, unif.c and extended to handle both the old and new
uniform vectors.

* unif.h, unif.c (scm_uniform_vector_ref, scm_array_ref): Renamed
the former to the latter.
(scm_uniform_vector_length, scm_uniform_element_size): Moved to
srfi-4.h, srfi-4.c.
(scm_make_uve): Call scm_make_s8vector for #\nul prototype.
(scm_array_p, scm_array_rank, scm_array_dimensions,
scm_transpose_array, scm_enclose_array, scm_array_ref, scm_cvref,
scm_array_set_x, scm_array_contents, scm_uniform_array_read_x,
scm_array_to_list, scm_array_prototype): Handle srfi-4 uniform
vectors.  Removed code for scm_tc7_byvect.
(scm_dimensions_to_uniform_array): Fill array with 0 when
prototype is #\nul.
(scm_i_print_array_dimension, scm_i_legacy_tag,
scm_i_print_array): New.
(scm_raprin1): Call scm_i_print_array for arrays.  Removed code
for scm_tc7_byvect.

libguile/srfi-4.i.c

@@ -15,6 +15,10 @@
    The tag name of the vector, for example u8.  The tag is used to
    form the function names and is included in the docstrings, for
    example.
+
+   - CTYPE
+
+   The C type of the elements, for example scm_t_uint8.
 */
 
 /* The first level does not expand macros in the arguments. */
@@ -113,6 +117,13 @@ SCM_DEFINE (F(scm_list_to_,TAG,vector), "list->"S(TAG)"vector", 1, 0, 0,
 }
 #undef FUNC_NAME
 
+CTYPE *
+F(scm_,TAG,vector_elements) (SCM obj)
+{
+  uvec_assert (TYPE, obj);
+  return (CTYPE *)SCM_UVEC_BASE (obj);
+}
+
 #undef paste
 #undef s_paste
 #undef stringify
@@ -122,3 +133,4 @@ SCM_DEFINE (F(scm_list_to_,TAG,vector), "list->"S(TAG)"vector", 1, 0, 0,
 
 #undef TYPE
 #undef TAG
+#undef CTYPE