[Patch]Fix the output of argument "options" for wait4, waitpid and waitid

[Frank Ch. Eigler]

Cai Fei <caifei@cn.fujitsu.com> writes:

> The system calls wait4, waitpid and waitid has an argument "int options".
>[...]
> and the values of WSTOPPED and WUNTRACED are equal.

It looks like all the matching names have matching values across the
system calls (which makes sense).  So why not just add WNOWAIT to the
_wait4_opt_str(), and perhaps rename it to indicate that it accepts a
union of all the wait* options?

- FChE