randread: run 2x faster on 64-bit hosts, don't assume no padding bits

randread: run 2x faster on 64-bit hosts, don't assume no padding bits

* gl/lib/rand-isaac.c: 	Remove the I/O; this belongs elsewhere.
Add support for ISAAC64.  Port to hosts with padding bits.
Add self to author list.  Include <limits.h>, for CHAR_BIT.
Don't include string.h, sys/time.h, unistd.h.
(min, just): New functions.
(IF32): New macros.
(ind, ISAAC_STEP, isaac_refill, mix, isaac_init, isaac_seed):
Add support for ISAAC64.  Port to hosts with padding bits.
(ind): Now an inline function rather than a macro; no need for it
to be a macro with modern compilers.
(ISAAC_STEP): Renamed from isaac_step, since it's not function-like.
Don't bother to pass args that are always the same.  All uses changed.
(ISAAC_STEP, ISAAC_SEED): Move to inside the only function body
that can use it.
(ISAAC_MIX): Renamed from isaac_mix, since it's now a macro and is
no longer function-like.  Don't bother saving and restoring state;
no longer needed now that we're not a function.  All uses changed.
(isaac_seed_start, isaac_seed_data, isaac_seed_finish): Remove.
(isaac_seed): Take just the one arg; the caller now sets s->m.
* gl/lib/rand-isaac.h: Use _GL_RAND_ISAAC_H to protect, instead
of RAND_ISAAC_H.  Try out " #" rather than "# " for indenting.
(ISAAC_BITS_LOG, ISAAC_BITS): New macros.
(ISAAC_WORDS_LOG): Renamed from ISAAC_LOG.
(isaac_word): New type.  All uses of uint32_t changed to isaac_word,
to support ISAAC64.
(struct isaac_state): Rename member MM to M, and make it public.
(isaac_seed, isaac_refill): Adjust to new API.
* gl/lib/randread.c: Include sys/time.h.
(get_nonce): New function, containing the nonce stuff that used
to be in rand-isaac.c but better belongs here.
(randread_new): Use it.
* gl/modules/randread (Depends-on): Add inline.
* gl/modules/randread-tests: New file.
* gl/tests/test-rand-isaac.c: New file.