Merge branch 'branch-2.6' into maint

* origin/branch-2.6:
  regen
  yacc.c: do not define location support when not using locations
  maint: be compilable with GCC 4.0
  tests: address a warning from GCC 4.4
  tests: don't use options that Clang does not support
  tests: restore the tests on -Werror
  regen
  parse-gram: update the Bison interface
  fix comment

src/getargs.c

@@ -49,7 +49,7 @@
 #include "quote.h"
 #include "uniqstr.h"
 
-bool debug_flag;
+bool debug;
 bool defines_flag;
 bool graph_flag;
 bool xml_flag;
@@ -665,7 +665,7 @@ getargs (int argc, char *argv[])
 	break;
 
       case 't':
-	debug_flag = true;
+	debug = true;
 	break;
 
       case 'v':