tests: fix incomplete Qt 6 support

The "frameworks/4 qt" test covers Qt 4 and 5. There is already Qt 6 code
in the test but it is incomplete because translations are missing and Qt
6 requires C++17 or later to compile.

test cases/frameworks/4 qt/meson.build

@@ -1,6 +1,6 @@
-project('qt4 and 5 build test', 'cpp',
-  # Qt5 now requires C++ 11 support
-  default_options : ['cpp_std=c++11'])
+project('qt4, qt5, and qt6 build test', 'cpp',
+  # Qt6 requires C++ 17 support
+  default_options : ['cpp_std=c++17'])
 
 qt5_modules = ['Widgets']
 qt6_modules = ['Widgets']

test cases/frameworks/4 qt/qt6_lang.qrc

@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/lang">
+        <file>qt6embedded_fr.qm</file>
+    </qresource>
+</RCC>
+

test cases/frameworks/4 qt/qt6core_fr.ts

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="fr_FR">
+<context>
+    <name>QObject</name>
+    <message>
+        <location filename="q5core.cpp" line="23"/>
+        <source>Translate me!</source>
+        <translation>Traduisez moi!</translation>
+    </message>
+</context>
+</TS>

test cases/frameworks/4 qt/qt6embedded_fr.ts

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="fr_FR">
+<context>
+    <name>QObject</name>
+    <message>
+        <location filename="q5core.cpp" line="23"/>
+        <source>Translate me!</source>
+        <translation>Traduisez moi!</translation>
+    </message>
+</context>
+</TS>