don't use annoying and unneeded in C++ casts of NULL to "T *" in all other files neither

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58227 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/datetime.h

@@ -1270,7 +1270,7 @@ public:
     inline wxLongLong GetValue() const;
 
     // a helper function to get the current time_t
-    static time_t GetTimeNow() { return time((time_t *)NULL); }
+    static time_t GetTimeNow() { return time(NULL); }
 
     // another one to get the current time broken down
     static struct tm *GetTmNow()