Access to more .NET flags, especially "Compiled"

[Davidebyzero]

Feature

Ideally all .NET regex flags should be accessible. The ones that currently aren't are Compiled, RightToLeft, ECMAScript, and CultureInvariant.

But RegexOptions.Compiled is especially important – I wouldn't much mind if this were the only flag added. It can make regexes run much faster.

It can even prevent certain errors from being thrown, for example in my regex that matches primes in decimal, without the Compiled flag, it throws an error on numbers ≥21, but with that flag, it works fine. (This can be worked around with a 4 byte longer regex, but that's beside the point.) Note though that some preliminary testing suggests that on the very latest version of .NET, a bug may prevent my regex from working properly in Compiled mode (matching every number instead of just primes).