QMLEngine is not compatible with QAbstractFileEngine on unix

bool exists = false;
#ifdef Q_OS_UNIX
struct stat statBuf;
// XXX Avoid encoding entire path. Should store encoded dirpath in cache
if (::stat(QFile::encodeName(path).constData(), &statBuf) == 0)
    exists = S_ISREG(statBuf.st_mode);
#else
exists = QFile::exists(path);
#endif
fileSet->insert(fileName, new bool(exists));
if (exists)
    absoluteFilePath = path;