Make wxLog::EnableLogging() and wxLogNull thread-specific.

Disabling logging in a single thread (even the main one) shouldn't disable
logs from the background threads which should disable their logging themselves
as/if needed.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61423 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/private/threadinfo.h

@@ -30,7 +30,18 @@ class WXDLLIMPEXP_FWD_BASE wxLog;
 // NB: this must be a POD to be stored in TLS
 struct wxThreadSpecificInfo
 {
+    // the thread-specific logger or NULL if the thread is using the global one
+    // (this is not used for the main thread which always uses the global
+    // logger)
     wxLog *logger;
+
+    // true if logging is currently disabled for this thread (this is also not
+    // used for the main thread which uses wxLog::ms_doLog)
+    //
+    // NB: we use a counter-intuitive "disabled" flag instead of "enabled" one
+    //     because the default, for 0-initialized struct, should be to enable
+    //     logging
+    bool loggingDisabled;
 };
 
 // currently this is defined in src/common/log.cpp