* Short options may be bundled, e.g. `-a -b` can be specified as `-ab`.
* Boolean long options can be 'negated' (or 'unset') by prepending
- `no-`, e.g. `\--no-abbrev` instead of `\--abbrev`.
+ `no-`, e.g. `\--no-abbrev` instead of `\--abbrev`. Conversely,
+ options that begin with `no-` can be 'negated' by removing it.
* Options and non-option arguments can clearly be separated using the `\--`
option, e.g. `-a -b \--option \-- \--this-is-a-file` indicates that
"auto", set `int_var` to 1 if stdout is a tty or a pager,
0 otherwise.
+`OPT_NOOP_NOARG(short, long)`::
+ Introduce an option that has no effect and takes no arguments.
+ Use it to hide deprecated options that are still to be recognized
+ and ignored silently.
+
The last element of the array must be `OPT_END()`.