clarified what this file covers

docs/COPYING

@@ -1,4 +1,11 @@
 
+Some parts of Mesa are copyrighted under the GNU LGPL.  See the
+Mesa/docs/COPYRIGHT file for details.
+
+The following is the standard GNU copyright file.
+----------------------------------------------------------------------
+
+
 		  GNU LIBRARY GENERAL PUBLIC LICENSE
 		       Version 2, June 1991