Adding a bool property for QLocale which indicates if AM/PM suffixes are used or not in the locale

QLocale returns always "AM" for amText and "PM" for pmText. Currently there is no good way to tell whether a locale expects 24h without AM/PM or 12h based time with AM/PM.

Some languages do not have a well defined amText/pmText therefore the API should give some kind of indication that the locale does not use them. That indication could be an explicit bool property like "hasAmPm" or "prefer24hBasedTime" which would indicate that information directly. Alternatively there could be an exception or a special value, for example, "<undefined for de_DE>". Some kind of indication of this to the programmer would be great.