qt5: Compile with -DQT_NO_CAST_FROM_BYTEARRAY

Bug #100311
diff --git a/qt5/src/poppler-private.h b/qt5/src/poppler-private.h
index ac384a4..fed4f26 100644
--- a/qt5/src/poppler-private.h
+++ b/qt5/src/poppler-private.h
@@ -92,7 +92,7 @@
 #ifdef _WIN32
 		doc = new PDFDoc((wchar_t *)filePath.utf16(), filePath.length(), ownerPassword, userPassword);
 #else
-		GooString *fileName = new GooString(QFile::encodeName(filePath));
+		GooString *fileName = new GooString(QFile::encodeName(filePath).constData());
 		doc = new PDFDoc(fileName, ownerPassword, userPassword);
 #endif