cut: fix handling of overlapping ranges

This issue was introduced in commit v8.21-43-g3e466ad

* src/cut.c (set_fields): Process all range pairs when merging.
* tests/misc/cut-huge-range.sh: Add a test for this edge case.
Also fix an issue where we could miss reported errors due
to truncation of the 'err' file.
cut: improve performance, especially with --output-delimiter

Use a sentinel value that's checked implicitly, rather than
a bit array, to determine if an item should be output.

Benchmark results for this change are:

$ yes abcdfeg | head -n1MB > big-file

$ for c in orig sentinel; do
    src/cut-$c 2>/dev/null
    echo -ne "\n== $c =="
    time src/cut-$c -b1,3 big-file > /dev/null
  done
== orig ==
real    0m0.049s
user    0m0.044s
sys     0m0.005s

== sentinel ==
real    0m0.035s
user    0m0.032s
sys     0m0.002s

 ## Again with --output-delimiter ##
$ for c in orig sentinel; do
    src/cut-$c 2>/dev/null
    echo -ne "\n== $c =="
    time src/cut-$c -b1,3 --output-delimiter=: big-file > /dev/null
  done
== orig ==
real    0m0.106s
user    0m0.103s
sys     0m0.002s

== sentinel ==
real    0m0.055s
user    0m0.052s
sys     0m0.003s

eol_range_start: Removed. 'n-' is no longer treated specially,
and instead SIZE_MAX is set for the 'hi' limit, and tested implicitly.
complement_rp: Used to complement 'rp' when '--complement' is specified.
ADD_RANGE_PAIR: Macro renamed to 'add_range_pair' function.
* tests/misc/cut-huge-range.sh: Adjust to the SENTINEL value.
Also remove the overlapping range test as this is no longer
dependent on large ranges and also is already handled with
the EOL-subsumed-3 test in cut.pl.
id: with -Z, show SMACK security context

Adds an optional dependency on libsmack.

* m4/jm-macros.m4: Look for the smack library/header.
* src/id.c (main): Output the smack context if available.
* src/local.mk: Link with libsmack if available.
* NEWS: Mention the new feature.