misc: fix XDG_CURRENT_DESKTOP comparison

Change-Id: I69f60964de48c770d5467c3231430a49b31e411e
GitLab: #603

src/main.cpp

@@ -62,9 +62,12 @@ main(int argc, char* argv[])
     QList<char*> qtWebEngineChromiumFlags;
 
 #ifdef Q_OS_LINUX
-    if (!getenv("QT_QPA_PLATFORMTHEME")
-        && !(getenv("XDG_CURRENT_DESKTOP") == "KDE" || getenv("XDG_CURRENT_DESKTOP") == "GNOME"))
+    if (!getenv("QT_QPA_PLATFORMTHEME")) {
+        auto xdgEnv = qgetenv("XDG_CURRENT_DESKTOP");
+        if (xdgEnv != "KDE" && xdgEnv != "GNOME") {
             setenv("QT_QPA_PLATFORMTHEME", "gtk3", true);
+        }
+    }
     setenv("QML_DISABLE_DISK_CACHE", "1", true);
 
     /*