Add wxFSW_EVENT_ATTRIB wxFileSystemWatcher flag.

This flag allows to monitor changes to the file attributes, such as file
modification time.

This patch adds the flag, support for it under Linux and the corresponding
modifications to the sample and the test suite.

Closes #14833.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72977 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/fswatcher.h

@@ -248,6 +248,15 @@ enum wxFSWFlags
      */
     wxFSW_EVENT_ACCESS = 0x10,
 
+    /**
+        The item's metadata was changed, e.g.\ its permissions or timestamps.
+
+        This event is currently only detected under Linux.
+
+        @since 2.9.5
+     */
+    wxFSW_EVENT_ATTRIB = 0x20,
+
     /**
         A warning condition arose.
 
@@ -257,7 +266,7 @@ enum wxFSWFlags
         more events will still be coming in the future, unlike for the error
         condition below.
      */
-    wxFSW_EVENT_WARNING = 0x20,
+    wxFSW_EVENT_WARNING = 0x40,
 
     /**
         An error condition arose.
@@ -266,11 +275,11 @@ enum wxFSWFlags
         and the program can stop watching the directories currently being
         monitored.
     */
-    wxFSW_EVENT_ERROR = 0x40,
+    wxFSW_EVENT_ERROR = 0x80,
 
     wxFSW_EVENT_ALL = wxFSW_EVENT_CREATE | wxFSW_EVENT_DELETE |
                          wxFSW_EVENT_RENAME | wxFSW_EVENT_MODIFY |
-                         wxFSW_EVENT_ACCESS |
+                         wxFSW_EVENT_ACCESS | wxFSW_EVENT_ATTRIB |
                          wxFSW_EVENT_WARNING | wxFSW_EVENT_ERROR
 };