reimplement srfi-4 vectors on top of bytevectors

reimplement srfi-4 vectors on top of bytevectors

* libguile/srfi-4.h:
* libguile/srfi-4.c (scm_make_srfi_4_vector): New function, exported by
  (srfi srfi-4 gnu).
* libguile/srfi-4.i.c: Removed.
* module/srfi/srfi-4.scm:
* module/srfi/srfi-4/gnu.scm: Reimplement srfi-4 vectors on top of
  bytevectors. The implementation is mostly in Scheme now.

* test-suite/tests/unif.test: Update to use (srfi srfi-4 gnu).

* libguile/bytevectors.c (bytevector_ref_c32, bytevector_ref_c64)
  (bytevector_set_c32, bytevector_set_c64): Fix some embarrassing bugs.
  Still need to do an upper bounds check.

* libguile/deprecated.h: Remove deprecated array functions:
  scm_i_arrayp, scm_i_array_ndim, scm_i_array_mem, scm_i_array_v,
  scm_i_array_base, scm_i_array_dims, and the deprecated macros:
  SCM_ARRAYP, SCM_ARRAY_NDIM, SCM_ARRAY_CONTP, SCM_ARRAY_MEM,
  SCM_ARRAY_V, SCM_ARRAY_BASE, SCM_ARRAY_DIMS.
* libguile/deprecated.c (scm_uniform_vector_read_x)
  (scm_uniform_vector_write, scm_uniform_array_read_x)
  (scm_uniform_array_write): Newly deprecated functions.

* libguile/generalized-arrays.c (scm_array_type): Remove the bytevector
  hack.

* libguile/objcodes.c (scm_bytecode_to_objcode, scm_objcode_to_bytecode):
  Rework to operate on bytevectors, as scm_make_u8vector now causes a
  module lookup, which can't be done e.g. when loading the VM boot
  program for psyntax-pp.go on a fresh bootstrap.

* libguile/objcodes.h (SCM_F_OBJCODE_IS_BYTEVECTOR):
  (SCM_OBJCODE_IS_BYTEVECTOR): s/U8VECTOR/BYTEVECTOR/.

* module/ice-9/boot-9.scm (the-scm-module): A terrible hack to pull in
  (srfi srfi-4), as the bindings are primarily there now. We'll worry
  about this later.