QStyleFactory::create ("gtk+") Seg fault

QStyle *pst = QStyleFactory::create ("gtk+")
will result in a Segmentation fault in this example program:

#include <QStyleFactory>
int main (int argc, char *argv[])
{
  QStyle *pst = QStyleFactory::create ("gtk+");
}

see attached typescript

"gtk+" is one of the available styles according to QStyleFactory::keys()

all other styles work fine with QApplication::setStyle
non-existent styles are handled properly, QStyleFactory::create("no-such-style")
returns 0 as expected