Support long directive names in the `{$IFOPT}` directive

[cirras]

Prerequisites

• This improvement has not already been suggested.
• This improvement would be generally useful, not specific to my code or setup.

Engine area

Delphi language support

Improvement description

Delphi 13 has added support for long directive names in {$IFOPT}.

We'll need to add support to the CompilerDirectiveParser.

See

• $IFOPT: Long directives support

Rationale

Delphi 13 support.