Add wxVersionInfo and functions returning it for 3rd party libraries.

Add simple wxVersionInfo class holding the version information.

Also add GetLibraryVersionInfo() static method to wx{JPEG,PNG,TIFF}Handler,
wxStyledTextCtrl and wxXmlDocument classes and wxGetZlibVersionInfo() and
wxGetLibraryVersionInfo() global functions using it.

Closes #12690.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66259 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/xml/xml.cpp

@@ -30,6 +30,7 @@
 #include "wx/zstream.h"
 #include "wx/strconv.h"
 #include "wx/scopedptr.h"
+#include "wx/versioninfo.h"
 
 #include "expat.h" // from Expat
 
@@ -1035,4 +1036,12 @@ bool wxXmlDocument::Save(wxOutputStream& stream, int indentstep) const
            OutputString(stream, wxS("\n"), convMem.get(), convFile.get());
 }
 
+/*static*/ wxVersionInfo wxXmlDocument::GetLibraryVersionInfo()
+{
+    return wxVersionInfo("expat",
+                         XML_MAJOR_VERSION,
+                         XML_MINOR_VERSION,
+                         XML_MICRO_VERSION);
+}
+
 #endif // wxUSE_XML