patch to yacc.c and lalr1.cc to avoid warning with pgcc 5.2-1

[Paul Eggert]

http://lists.gnu.org/archive/html/bug-bison/2005-01/msg00025.html

contains this diagnostic:

   "input.cc", line 468: warning: label "yyerrorlab" was declared but never
             referenced
     yyerrorlab:
     ^

apparently because pgcc 5.2-1 behaves like CC with respect to the warning,
but it doesn't define __GNUC__.  I installed the following patch to work
around this:

2005-01-07  Paul Eggert  <address@hidden>

        * data/yacc.c (yyparse): Pacify non-GCC compilers about yyerrorlab
        being defined and not used.
        * data/lalr1.cc (yyparse): Likewise.
        Use "if (false)" rather than "if (0)".

Index: data/yacc.c
===================================================================
RCS file: /cvsroot/bison/bison/data/yacc.c,v
retrieving revision 1.79
diff -p -u -r1.79 yacc.c
--- data/yacc.c 22 Dec 2004 21:19:47 -0000      1.79
+++ data/yacc.c 8 Jan 2005 05:21:21 -0000
@@ -1,7 +1,8 @@
 m4_divert(-1)                                                       -*- C -*-
 
 # Yacc compatible skeleton for Bison
-# Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004
+
+# Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005
 # Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
@@ -1170,12 +1171,11 @@ yyerrlab:
 `---------------------------------------------------*/
 yyerrorlab:
 
-#ifdef __GNUC__
-  /* Pacify GCC when the user code never invokes YYERROR and the label
-     yyerrorlab therefore never appears in user code.  */
+  /* Pacify compilers like GCC when the user code never invokes
+     YYERROR and the label yyerrorlab therefore never appears in user
+     code.  */
   if (0)
      goto yyerrorlab;
-#endif
 
 ]b4_location_if([[  yyerror_range[0] = yylsp[1-yylen];
   yylsp -= yylen;
Index: data/lalr1.cc
===================================================================
RCS file: /cvsroot/bison/bison/data/lalr1.cc,v
retrieving revision 1.80
diff -p -u -r1.80 lalr1.cc
--- data/lalr1.cc       26 Dec 2004 05:42:27 -0000      1.80
+++ data/lalr1.cc       8 Jan 2005 05:21:21 -0000
@@ -1,6 +1,8 @@
 m4_divert(-1)
+
 # C++ skeleton for Bison
-# Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+
+# Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -747,12 +749,11 @@ yyerrlab:
 `---------------------------------------------------*/
 yyerrorlab:
 
-#ifdef __GNUC__
-  /* Pacify GCC when the user code never invokes YYERROR and the label
-     yyerrorlab therefore never appears in user code.  */
-  if (0)
+  /* Pacify compilers like GCC when the user code never invokes
+     YYERROR and the label yyerrorlab therefore never appears in user
+     code.  */
+  if (false)
      goto yyerrorlab;
-#endif
 
   yyerror_range_[0] = yylocation_stack_[yylen_ - 1];
   yypop_ (yylen_);