Remove arbitrary limit of 2**31 entries in hash tables.

Remove arbitrary limit of 2**31 entries in hash tables.

* category.c (hash_get_category_set): Use 'EMACS_UINT' and 'EMACS_INT'
for hashes and hash indexes, instead of 'unsigned' and 'int'.
* ccl.c (ccl_driver): Likewise.
* charset.c (Fdefine_charset_internal): Likewise.
* charset.h (struct charset.hash_index): Likewise.
* composite.c (get_composition_id, gstring_lookup_cache):
(composition_gstring_put_cache): Likewise.
* composite.h (struct composition.hash_index): Likewise.
* dispextern.h (struct image.hash): Likewise.
* fns.c (next_almost_prime, larger_vector, cmpfn_eql):
(cmpfn_equal, cmpfn_user_defined, hashfn_eq, hashfn_eql):
(hashfn_equal, hashfn_user_defined, make_hash_table):
(maybe_resize_hash_table, hash_lookup, hash_put):
(hash_remove_from_table, hash_clear, sweep_weak_table, SXHASH_COMBINE):
(sxhash_string, sxhash_list, sxhash_vector, sxhash_bool_vector):
(Fsxhash, Fgethash, Fputhash, Fmaphash): Likewise.
* image.c (make_image, search_image_cache, lookup_image):
(xpm_put_color_table_h): Likewise.
* lisp.h (struct Lisp_Hash_Table): Likewise, for 'count', 'cmpfn',
and 'hashfn' members.
* minibuf.c (Ftry_completion, Fall_completions, Ftest_completion):
Likewise.
* print.c (print): Likewise.
* alloc.c (allocate_vectorlike): Check for overflow in vector size
calculations.
* ccl.c (ccl_driver): Check for overflow when converting EMACS_INT
to int.
* fns.c, image.c: Remove unnecessary static decls that would otherwise
need to be updated by these changes.
* fns.c (make_hash_table, maybe_resize_hash_table): Check for integer
overflow with large hash tables.
(make_hash_table, maybe_resize_hash_table, Fmake_hash_table):
Prefer the faster XFLOAT_DATA to XFLOATINT where either will do.
(SXHASH_REDUCE): New macro.
(sxhash_string, sxhash_list, sxhash_vector, sxhash_bool_vector):
Use it instead of discarding useful hash info with large hash values.
(sxhash_float): New function.
(sxhash): Use it.  No more need for "& INTMASK" due to above changes.
* lisp.h (FIXNUM_BITS): New macro, useful for SXHASH_REDUCE etc.
(MOST_NEGATIVE_FIXNUM, MOST_POSITIVE_FIXNUM, INTMASK): Rewrite
to use FIXNUM_BITS, as this simplifies things.
(next_almost_prime, larger_vector, sxhash, hash_lookup, hash_put):
Adjust signatures to match updated version of code.
(consing_since_gc): Now EMACS_INT, since a single hash table can
use more than INT_MAX bytes.