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/generic/listctrl.cpp

@@ -1804,7 +1804,8 @@ void wxListHeaderWindow::DoDrawRect( wxDC *dc, int x, int y, int w, int h )
 
     gtk_paint_box (m_wxwindow->style, GTK_PIZZA(m_wxwindow)->bin_window,
                    state, GTK_SHADOW_OUT,
-                   (GdkRectangle*) NULL, m_wxwindow, "button",
+                   (GdkRectangle*) NULL, m_wxwindow,
+                   (char *)"button", // const_cast
                    x-1, y-1, w+2, h+2);
 #elif defined( __WXMAC__  )
     const int m_corner = 1;