Section 2.4: Operations on 16-bit Integers.

Section 2.4: Operations on 16-bit Integers.

* modules/r6rs/bytevector.scm: Export the s16/u16 procedures.

* src/bytevector.c (INT_TYPE, INT_SWAP, INT_VALID_P): New macros.
  (INTEGER_ACCESSOR_PROLOGUE, INTEGER_REF, INTEGER_NATIVE_REF,
  INTEGER_SET, INTEGER_NATIVE_SET): New macros.
  (OCTET_ACCESSOR_PROLOGUE): Removed.
  (scm_r6rs_bytevector_{u8,s8}_{ref,set_x}): Use the new macros.
  (GENERIC_INTEGER_ACCESSOR_PROLOGUE, GENERIC_INTEGER_REF,
  GENERIC_INTEGER_SET): New name for the macros previously same-named but
  without `GENERIC_'.
  (scm_r6rs_bytevector_{u16,s16}_{ref,set_x}): New.

* tests/bytevector.test: New tests.

git-archimport-id: lcourtes@laas.fr--2006-libre/guile-r6rs-libs--devo--0--patch-4