Minor code cleanups, mostly to use more accurate

Minor code cleanups, mostly to use more accurate
types and to remove unnecessary casts.
(min, max): Remove.  All uses changed to MIN and MAX.
(hard_lc_collate, hard_LC_TIME, struct buffer.eof, struct
keyfield.skipsblanks, struct keyfield.skipeblanks, struct
keyfield.numeric, struct keyfield.general_numeric, struct
keyfield.month, struct keyfield.reverse, reverse, unique,
have_read_stdin): Now bool, not int.  All uses changed.
(eolchar): Now char, not int.
(struct keyfield.ignore): Now bool const *, not int *.
(struct keyfield.translate): Now char const *, not char *.
(struct month.name): Likewise.
(blanks, nonprinting, nondictionary): Now bool[], not int[].
(cleanup, inittables, keycompare, check, mergefps, first_same_file,
check, sort, main): Use const * pointers when possible.
(month_cmp): Rewrite to avoid casts.
(inittables): Initialize tables unconditionally, to avoid branches.
(fillbuf): Return bool, not int.  All uses changed.
(fillbuf, keycompare, new_key, main):
Use SIZE_MAX rather than (size_t) -1.
(trailing_blanks): Renamed from trim_trailing_blanks.
Return the number of blanks to trim.  All uses changed.
(getmonth): Use trailing_blanks rather than open code.
(keycompare): Do not cast char * to unsigned char *; not needed.
CMP_WITH_IGNORE converts args to UCHAR, so no need to convert it
ourselves.
(compare, main): Use | rather than || to avoid jumps.
Replace "diff = NONZERO (alen)" with "diff = 1", since alen must
be nonzero there.
(check, first_same_file, sort, main):
Use bool instead of int local vars when possible.
(check): Merge the old 'checkfp' and 'check' into a single function,
that returns a boolean (true if the file was ordered).
All uses changed.
(main): Use int instead of unsigned for iterating through nsigs.
Rename local var "posix_pedantic" to "posixly_correct".