Fixed removeIf for Qt version

Signed-off-by: Trial97 <alexandru.tripon97@gmail.com>

launcher/ui/pages/modplatform/ResourceModel.cpp

@@ -458,7 +458,39 @@ void ResourceModel::infoRequestSucceeded(QJsonDocument& doc, ModPlatform::Indexe
 
 void ResourceModel::removePack(QString& rem)
 {
-    m_selected.removeIf([&rem](ModPlatform::IndexedPack i) { return rem == i.name; });
+    auto pred = [&rem](ModPlatform::IndexedPack i) { return rem == i.name; };
+#if QT_VERSION >= QT_VERSION_CHECK(6, 1, 0)
+    m_selected.removeIf(pred);
+#else
+    {  // well partial implementation of remove_if in case the QT Version is not high enough
+        const auto cbegin = m_selected.cbegin();
+        const auto cend = m_selected.cend();
+        const auto t_it = std::find_if(cbegin, cend, pred);
+        auto result = std::distance(cbegin, t_it);
+        if (result != m_selected.size()) {
+            // now detach:
+            const auto e = m_selected.end();
+
+            auto it = std::next(m_selected.begin(), result);
+            auto dest = it;
+
+            // Loop Invariants:
+            // - it != e
+            // - [next(it), e[ still to be checked
+            // - [c.begin(), dest[ are result
+            while (++it != e) {
+                if (!pred(*it)) {
+                    *dest = std::move(*it);
+                    ++dest;
+                }
+            }
+
+            result = std::distance(dest, e);
+            m_selected.erase(dest, e);
+        }
+    }
+#endif
+    // m_selected.removeAt(qsizetype i)
     auto pack = std::find_if(m_packs.begin(), m_packs.end(), [&rem](ModPlatform::IndexedPack i) { return rem == i.name; });
     if (pack == m_packs.end()) {  // ignore it if is not in the current search
         return;