Warnings due to Qt 6.8.0 deprecating the constructor of QDateTime taking Qt::TimeSpec

[bobhairgrove]

There needs to be a minor change in the two files quazip_qt_compat.h and quazipfileinfo.cpp when compiling with Qt 6.8.0 or later. Everything before that version compiles without any warnings (on GCC, but I disabled warnings when compiling with MSVC). (EDIT: using Qt 5.15.5 still compiles OK with the new #if ... #else guards in place).

The warning given when compiling the code with Qt 6.8.0 (using GCC 11.4.0 on Linux Ubuntu 22.04) is:

In file included from ../../../3rd_party/quazip/quazip.h:30,
                 from ../../../3rd_party/quazip/JlCompress.h:29,
                 from ../../../3rd_party/quazip/JlCompress.cpp:26:
../../../3rd_party/quazip/quazip_qt_compat.h: 
../../../3rd_party/quazip/quazip_qt_compat.h:110:59: 
In function ‘quint64 quazip_ntfs_ticks(const QDateTime&, int)’:
warning: ‘QDateTime::QDateTime(QDate, QTime, Qt::TimeSpec, int)’ is deprecated: 
Pass QTimeZone instead [-Wdeprecated-declarations]
  110 |     QDateTime base(QDate(1601, 1, 1), QTime(0, 0), Qt::UTC);

I tested using an #include guard:

// At line 106:
// this is not a deprecation but an improvement, for a change
#include <QtCore/QDateTime>
#if QT_VERSION >= QT_VERSION_CHECK(6,8,0)
inline quint64 quazip_ntfs_ticks(const QDateTime &time, int fineTicks) {
    QDateTime base(QDate(1601, 1, 1), QTime(0, 0), QTimeZone(Qt::UTC));
    return base.msecsTo(time) * 10000 + fineTicks;
}
#elif (QT_VERSION >= 0x040700)
// etc.

Also, in the file quazipfileinfo.cpp: #include at the top:

#include <QtCore/QDataStream>
#if QT_VERSION >= QT_VERSION_CHECK(6,8,0)
#include <QTimeZone>
#endif

Then at line 129:

#if QT_VERSION >= QT_VERSION_CHECK(6,8,0)
    QDateTime base(QDate(1601, 1, 1), QTime(0, 0), QTimeZone(Qt::UTC));
#else
    QDateTime base(QDate(1601, 1, 1), QTime(0, 0), Qt::UTC);
#endif
    dateTime = base.addMSecs(time / 10000);
// etc.

[bobhairgrove]

Since I am building QuaZip by including the source files in my application, I have no way of testing whether or not the proposed changes have implications for the build toolchain. That is why I have not forked the project and made a pull request, but rather just show the changes here. But the changes are very small, so I think it should be OK.