imic the
defined POSIX behaviour for REG_NEWLINE (see the following section).
<pre>
  REG_NOSPEC
</pre>
The PCRE2_LITERAL option is set when the regular expression is passed for
compilation to the native function. This disables all meta characters in the
pattern, causing it to be treated as a literal string. The only other options
that are allowed with REG_NOSPEC are REG_ICASE, REG_NOSUB, REG_PEND, and
REG_UTF. Note that REG_NOSPEC is not part of the POSIX standard.
<pre>
  REG_NOSUB
</pre>
When a pattern t