+ - The documentation now emphasizes that yylex and yyerror must be
+ declared before use. C99 requires this.
+
+ - Bison now parses C99 lexical constructs like UCNs and
+ backslash-newline within C escape sequences, as POSIX 1003.1-2001 requires.
+
+ - File names are properly escaped in C output. E.g., foo\bar.y is
+ output as "foo\\bar.y".
+
+ - Yacc command and library now available
+ The Bison distribution now installs a `yacc' command, as POSIX requires.
+ Also, Bison now installs a small library liby.a containing
+ implementations of Yacc-compatible yyerror and main functions.
+ This library is normally not useful, but POSIX requires it.
+
+ - Type clashes now generate warnings, not errors.
+
+ - If the user does not define YYSTYPE as a macro, Bison now declares it
+ using typedef instead of defining it as a macro.
+ For consistency, YYLTYPE is also declared instead of defined.
+
+* Other compatibility issues
+
+ - %union directives can now have a tag before the `{', e.g., the
+ directive `%union foo {...}' now generates the C code
+ `typedef union foo { ... } YYSTYPE;'; this is for Yacc compatibility.
+ The default union tag is `YYSTYPE', for compatibility with Solaris 9 Yacc.
+ For consistency, YYLTYPE's struct tag is now `YYLTYPE' not `yyltype'.
+ This is for compatibility with both Yacc and Bison 1.35.
+
+ - `;' is output before the terminating `}' of an action, for
+ compatibility with Bison 1.35.
+
+ - Bison now uses a Yacc-style format for conflict reports, e.g.,
+ `conflicts: 2 shift/reduce, 1 reduce/reduce'.
+
+ - `yystype' and `yyltype' are now obsolescent macros instead of being
+ typedefs or tags; they are no longer documented and are planned to be
+ withdrawn in a future release.
+
+* GLR parser notes
+
+ - GLR and inline
+ Users of Bison have to decide how they handle the portability of the
+ C keyword `inline'.
+
+ - `parsing stack overflow...' -> `parser stack overflow'
+ GLR parsers now report `parser stack overflow' as per the Bison manual.
+
+* Bison now warns if it detects conflicting outputs to the same file,
+ e.g., it generates a warning for `bison -d -o foo.h foo.y' since
+ that command outputs both code and header to foo.h.
+
+* #line in output files
+ - --no-line works properly.
+
+* Bison can no longer be built by a K&R C compiler; it requires C89 or
+ later to be built. This change originally took place a few versions
+ ago, but nobody noticed until we recently asked someone to try
+ building Bison with a K&R C compiler.
+\f