(UNSIGNED): Renamed from STRTOUXMAX_UNSIGNED.
(verify): New macro.
(INT): Renamed from uintmax_t.
(strtoumax, strtoull, strtoul): Remove.
(strtoimax, strtol, strtoll): New macros.
(strtoimax): Renamed from strtoumax. Interchange signed with unsigned.
Verify sizes at compile-time, not at run-time.
Prefer strtol to strtoll if both work.
(main): Remove.
(<stdlib.h>, <unistd.h>): Include if available.
("xalloc.h"): Include.
(xmalloc, xstrdup, free): Remove decls; no longer needed.
(xgetcwd): Don't assume sizes fit in 'unsigned'.
Check for overflow when path size gets too large.
Simplify failure code.
(NAMLEN): Remove macro.
(malloc, realloc): Remove decls.
(stpcpy): Likewise.
("xalloc.h"): Include.
(NAME_SIZE_DEFAULT): New macro.
(savedir): Use xmalloc / xrealloc to allocate memory.
Use NAME_SIZE_DEFAULT if name_size is negative or overflows to zero.
Skip "" directory entries.
Use strlen to calculate directory entry length, since the old method
is rarely used these days and isn't worth supporting.
Check for integer overflow when calculating allocation size.
Use memcpy to copy entries, instead of stpcpy.
Set errno properly when returning NULL.
Check for readdir error.
(textint): New typedef.
(parser_control): Changed from struct parser_control to typedef (for
consistency). Member year changed from int to textint. All uses changed.
(YYSTYPE): Removed; replaced by %union with int and textint members.
(tID): Removed; not used.
(tDAY, tDAY_UNIT, tDAYZONE, tHOUR_UNIT, tID, tLOCAL_ZONE, tMERIDIAN,
tMINUTE_UNIT, tMONTH, tMONTH_UNIT tSEC_UNIT, tSNUMBER, tUNUMBER,
tYEAR_UNIT, tZONE, o_merid): Now of type <intval>.
(tSNUMBER, tUNUMBER): Now of type <textintval>.
(date, number, to_year): Use width of number in digits, not its value,
to determine whether it's a 2-digit year, or a 2-digit time.
(yylex): Store number of digits of numeric tokens.
Return '?' for unknown identifiers, rather than (unused) tID.
