qdoc: incorrect handling of '#if defined' preprocessor statement

The following check should resolve to true:

#if QT_DEPRECATED_SINCE(5, 11) && !defined QT_NO_TEXTDATE

Because QT_NO_TEXTDATE is not in qdoc's 'defines' variable, and QT_DEPRECATED_SINCE(.) is *not in 'falsehoods'. However, it resolves to false - this is because qdoc expects defined condition to be wrapped in parentheses, which is always isn't.