fix: store IPC file in application directory (#5226)

src/singletons/Paths.cpp

@@ -140,6 +140,13 @@ void Paths::initSubDirectories()
     this->pluginsDirectory = makePath("Plugins");
     this->themesDirectory = makePath("Themes");
     this->crashdumpDirectory = makePath("Crashes");
+#ifdef Q_OS_WIN
+    this->ipcDirectory = makePath("IPC");
+#else
+    // NOTE: We do *NOT* use IPC on non-Windows platforms.
+    // If we start, we should re-consider this directory.
+    this->ipcDirectory = "/tmp";
+#endif
 }
 
 }  // namespace chatterino

src/singletons/Paths.hpp

@@ -39,6 +39,11 @@ public:
     // Custom themes live here. <appDataDirectory>/Themes
     QString themesDirectory;
 
+    // Directory for shared memory files.
+    // <appDataDirectory>/IPC   on Windows
+    // /tmp                     elsewhere
+    QString ipcDirectory;
+
     bool createFolder(const QString &folderPath);
     [[deprecated("use Modes::instance().portable instead")]] bool isPortable()
         const;