glr2.cc: the example requires Bison 3.8

[Akim Demaille]

commit 83f2eb3737b8037c79796dcb1648818d50897fc8
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Thu Dec 31 08:20:23 2020 +0100

    glr2.cc: the example requires Bison 3.8
    
    This will save us from generating the position.hh file.
    
    * src/parse-gram.y: Claim we are 3.8.
    * examples/c++/glr/c++-types.yy: Require 3.8.

diff --git a/examples/c++/glr/c++-types.yy b/examples/c++/glr/c++-types.yy
index 20020723..c5fcf620 100644
--- a/examples/c++/glr/c++-types.yy
+++ b/examples/c++/glr/c++-types.yy
@@ -18,6 +18,7 @@
 /* Simplified C++ Type and Expression Grammar.
    Written by Paul Hilfinger for Bison's test suite.  */
 
+%require "3.8"
 %glr-parser
 %skeleton "glr2.cc"
 %define parse.assert
diff --git a/src/parse-gram.c b/src/parse-gram.c
index 82a10233..43496cbf 100644
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -237,7 +237,7 @@ typedef enum yysymbol_kind_t yysymbol_kind_t;
 
   /* Pretend to be at least that version, to check features published
      in that version while developping it.  */
-  static const char* api_version = "3.7";
+  static const char* api_version = "3.8";
 
   static int current_prec = 0;
   static location current_lhs_loc;
diff --git a/src/parse-gram.y b/src/parse-gram.y
index 3f2c0147..5fa2a3ad 100644
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -59,7 +59,7 @@
 
   /* Pretend to be at least that version, to check features published
      in that version while developping it.  */
-  static const char* api_version = "3.7";
+  static const char* api_version = "3.8";
 
   static int current_prec = 0;
   static location current_lhs_loc;