yydestroyGLRState prints unresolved semantic value

[Joel E. Denny]

Since this patch touches more than GLR-related code, I thought it would be 
best to ask for approval before committing.  Is this ok?

Joel

2006-01-05  Joel E. Denny  <address@hidden>

        * data/c.m4 (b4_yy_symbol_print_generate): In yy_symbol_print, accept
        !yyvaluep as signal that no semantic value is available to print.
        * data/glr.c (yydestroyGLRState): If state is not resolved, don't try
        to print a semantic value.

Index: data/c.m4
===================================================================
RCS file: /sources/bison/bison/data/c.m4,v
retrieving revision 1.50
diff -p -u -r1.50 c.m4
--- data/c.m4   4 Jan 2006 23:42:53 -0000       1.50
+++ data/c.m4   5 Jan 2006 23:30:20 -0000
@@ -464,7 +464,8 @@ m4_define_default([b4_yy_symbol_print_ge
 b4_location_if([, [[const YYLTYPE * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {
-  YYUSE (yyvaluep);
+  if (!yyvaluep)
+    return;
 ]b4_location_if([  YYUSE (yylocationp);
 ])dnl
 b4_parse_param_use[]dnl
Index: data/glr.c
===================================================================
RCS file: /sources/bison/bison/data/glr.c,v
retrieving revision 1.154
diff -p -u -r1.154 glr.c
--- data/glr.c  5 Jan 2006 21:07:54 -0000       1.154
+++ data/glr.c  5 Jan 2006 23:30:20 -0000
@@ -973,7 +973,7 @@ yydestroyGLRState (char const *yymsg, yy
        {
          YYFPRINTF (stderr, "%s unresolved ", yymsg);
          yy_symbol_print (stderr, yystos[yys->yylrState],
-                          &yys->yysemantics.yysval]b4_location_if([, 
&yys->yyloc])[]b4_user_args[);
+                          NULL]b4_location_if([, &yys->yyloc])[]b4_user_args[);
          YYFPRINTF (stderr, "\n");
        }
 #endif