Simplify, port and tune bool vector implementation.

Simplify, port and tune bool vector implementation.

* configure.ac (BITSIZEOF_SIZE_T, SIZEOF_SIZE_T): Remove.
* src/alloc.c (bool_vector_exact_payload_bytes)
(bool_vector_payload_bytes): Remove.
(bool_vector_fill): Return its argument.
* src/alloc.c (bool_vector_fill):
* src/lread.c (read1):
* src/print.c (print_object):
Simplify by using bool_vector_bytes.
* src/alloc.c (make_uninit_bool_vector):
New function, broken out from Fmake_bool_vector.
(Fmake_bool_vector): Use it.  Use tail call.
(make_uninit_bool_vector, vector_nbytes): Simplify size calculations.
* src/data.c (BITS_PER_ULL): New constant.
(ULLONG_MAX, count_one_bits_ll): Fall back on long counterparts
if long long versions don't exist.
(shift_right_ull): New function.
(count_one_bits_word): New function, replacing popcount_bits_word
macro.  Don't assume that bits_word is no wider than long long.
(count_one_bits_word, count_trailing_zero_bits):
Don't assume that bits_word is no wider than long long.
* src/data.c (bool_vector_binop_driver, bool_vector_not):
* src/fns.c (Fcopy_sequence):
* src/lread.c (read1):
Create an uninitialized destination, to avoid needless work.
(internal_equal): Simplify.
(Ffillarray): Prefer tail call.
* src/data.c (bool_vector_binop_driver): Don't assume bit vectors always
contain at least one word.
(bits_word_to_host_endian): Prefer if to #if.  Don't assume
chars are narrower than ints.
* src/data.c (Fbool_vector_count_matches, Fbool_vector_count_matches_at):
* src/fns.c (Fcopy_sequence):
Simplify and tune.
* src/lisp.h (bits_word, BITS_WORD_MAX, BITS_PER_BITS_WORD):
Don't try to port to hosts where bits_word values have holes; the
code wouldn't work there anyway.  Verify this assumption, though.
(bool_vector_bytes): New function.
(make_uninit_bool_vector): New decl.
(bool_vector_fill): Now returns Lisp_Object.