don't assign string literals to a char * variable

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@13434 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/dcpsg.cpp

@@ -1957,7 +1957,7 @@ void wxPostScriptDC::DoGetTextExtent(const wxString& string,
         lastStyle =  Style;
         lastWeight = Weight;
 
-        char *name = (char*) NULL;
+        const char *name = NULL;
 
         switch (Family)
         {