* src/system.h (CALLOC, MALLOC, REALLOC): Remove. All callers

* src/system.h (CALLOC, MALLOC, REALLOC): Remove.  All callers
changed to use xcalloc, xnmalloc, xnrealloc, respectively,
unless otherwise specified below.

* src/LR0.c (allocate_itemsets): Use xnmalloc, not xcalloc,
to allocate kernel_base, kernel_items, kernel_size, since
they needn't be initialized to 0.
(allocate_storgae): Likewise, for shiftset, redset, shift_symbol.
* src/closure.c (new_closure): Likewise, for itemset.
* src/derives.c (derives_compute): Likewise, for delts, derives, q.
* src/lalr.c (set_goto_map): Likewise, for temp_map.
(initialize_F): Likewise, for reads, edge, reads[i], includes[i].
(build_relations): Likewise for edge, states1, includes.
* src/nullable.c (nullable_compute): Likewise, for squeue, relts.
* src/reader.c (packgram): Likewise, for ritem, rules.
* src/reduce.c (nonterminals_reduce): Likewise for nontermmap.
* src/relation.c (relation_digraph): Likewise for VERTICES.
(relation_transpose): Likewise for new_R, end_R.
* src/symtab.c (symbols_token_translations_init): Likewise for
token_translations.
* src/tables.c (save_row): Likewise for froms, tos, conflict_tos.
(token_actions): Likewise for yydefact, actrow, conflrow,
conflict_list.
(save_column): Likewise for froms[symno], tos[symno].
(goto_actions): Likewise for state_count.
(pack_table): Likewise for base, pos, check.
(tables_generate): Likewise for width.

* src/LR0.c (set_states): Don't reuse kernel_size and kernel_base
for initial core.  Just have a separate core, so we needn't worry
about whether kernel_size and kernel_base are initialized.

* src/LR0.c (shift_symbol, redset, shiftset, kernel_base,
kernel_size, kernel_items): Remove unnecessary initialization.
* src/conflicts.c (conflicts): Likewise.
* src/derives.c (derives): Likewise.
* src/muscle_tablc (muscle_insert): Likewise.
* src/relation.c (relation_digraph): Likewise.
* src/tables.c (froms, tos, conflict_tos, tally, width, actrow, order,
conflrow, conflict_table, conflict_list, table, check):
Likewise.

* src/closure.c (new_closure): Arg is of type unsigned int, not int.
This is because all callers pass unsigned int.
* src/closure.h (new_closure): Likewise.

* src/lalr.c (initialize_F): Initialize reads[i] in all cases.
(build_relations): Initialize includes[i] in all cases.
* src/reader.c (packgram): Always initialize rules[ruleno].prec
and rules[ruleno].precsym.  Initialize members in order.
* src/relation.c (relation_transpose): Always initialize new_R[i]
and end_R[i].
* src/table.c (conflict_row): Initialize 0 at end of conflict_list.

* src/output.c (prepare_actions): Pass 0 instead of conflict_list[0];
conflict_list[0] was always 0, but now it isn't initialized.

* src/table.c (table_grow): When conflict_table grew, the grown
area wasn't cleared.  Fix this.