Mention thread-safety on Application class

Signed-off-by: falkTX <falktx@falktx.com>

dgl/Application.hpp

@@ -30,6 +30,8 @@ START_NAMESPACE_DGL
    There's no single/global application instance in DGL, and multiple windows can share the same app instance.
 
    In standalone mode an application will automatically quit its event-loop when all its windows are closed.
+
+   Unless stated otherwise, functions within this class are not thread-safe.
  */
 class Application
 {
@@ -61,6 +63,7 @@ public:
    /**
       Quit the application.
       This stops the event-loop and closes all Windows.
+      This function is thread-safe.
       @note This function is meant for standalones only, *never* call this from plugins.
     */
     void quit();
@@ -68,6 +71,7 @@ public:
    /**
       Check if the application is about to quit.
       Returning true means there's no event-loop running at the moment (or it's just about to stop).
+      This function is thread-safe.
     */
     bool isQuiting() const noexcept;
 

dgl/src/ApplicationPrivateData.cpp

@@ -34,7 +34,7 @@ static ThreadHandle getCurrentThreadHandle() noexcept
 #endif
 }
 
-static bool isThisMainThread(const ThreadHandle mainThreadHandle) noexcept
+static bool isThisTheMainThread(const ThreadHandle mainThreadHandle) noexcept
 {
 #ifdef DISTRHO_OS_WINDOWS
     return GetCurrentThread() == mainThreadHandle; // IsGUIThread ?
@@ -127,7 +127,7 @@ void Application::PrivateData::quit()
 {
     DISTRHO_SAFE_ASSERT_RETURN(isStandalone,);
 
-    if (! isThisMainThread(mainThreadHandle))
+    if (! isThisTheMainThread(mainThreadHandle))
     {
         if (! isQuittingInNextCycle)
         {