Workaround for OpenC daylight saving cache issue when using localtime_r.
Workaround for OpenC daylight saving cache issue when using localtime_r.

OpenC incorrectly caches DST information between localtime_r
calls, i.e. if previous call to localtime_r has been called for DST
affected date, also the second call will be affected by DST even
the date is such that DST should not be applied.

The workaround is to call mktime with non-DST affected date before
calling localtime_r. mktime call resets the OpenC internal DST cache
to right value and localtime_r will return correct values.

This commit can be reverted once Open C bug 9525 has been reverted.

AutoTest: Fixes tst_QDateTime::totime_t
Reviewed-by: Aleksandar Sasha Babic

igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt