+Changes in version 2.1a:
+
+* DJGPP support added.
+
+* %require "VERSION"
+ To specify that the grammar file depends on features implemented in
+ Bison version VERSION or higher.
+
+* lalr1.cc: The token and value types are now class members.
+ The tokens where defined as free form enums and cpp macros. YYSTYPE
+ was defined as a free form union. Both are now class members:
+ tokens are enumerations of the `yy::parser::token' struct, and the
+ semantic values have the `yy::parser::semantic_type' type.
+
+ If you do not want or can update to this scheme, the directive
+ `%define "global_tokens_and_yystype" "1"' triggers the global
+ definition of tokens and YYSTYPE. This change is suitable both
+ for previous releases of Bison, and this one.
+
+ If you wish to update, then make sure older version of Bison will
+ fail using `%require "2.1a"'.
+
+Changes in version 2.1, 2005-09-16: