Added wxCriticalSection::TryEnter() method.

This is similar to wxMutex::TryLock() and useful for the same reasons.

Closes #13638.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69883 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/thread.h

@@ -584,6 +584,14 @@ public:
     */
     void Enter();
 
+    /**
+        Try to enter the critical section (same as trying to lock a mutex).
+        If it can't, immediately returns false.
+
+        @since 2.9.3
+    */
+    bool TryEnter();
+
     /**
         Leave the critical section allowing other threads use the global data
         protected by it. There is no error return for this function.