fixes for the compilation warnings with Sun CC:

1. some fixes for "String literal to char * conversion" warnings (many
   more left in the *.xpm files)
2. fixes for "assignment of function to extern "C" function"
3. a few other miscellaneous ones


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@13478 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/string.cpp

@@ -2240,7 +2240,8 @@ static wxArrayString::CompareFunction gs_compareFunction = NULL;
 static bool gs_sortAscending = TRUE;
 
 // function which is called by quick sort
-static int LINKAGEMODE wxStringCompareFunction(const void *first, const void *second)
+extern "C" int LINKAGEMODE
+wxStringCompareFunction(const void *first, const void *second)
 {
   wxString *strFirst = (wxString *)first;
   wxString *strSecond = (wxString *)second;