reports: don't escape the labels

Currently we use "quotearg" to escape the strings output in Dot.  As a
result, if the user's locale is C for instance, all the non-ASCII are
escaped.  Unfortunately graphviz does not interpret this style of
escaping.

For instance:

    5 -> 2 [style=solid label="\"\303\221\303\271\341\271\203\303\251\342\204\235\303\264\""]

was displayed as a sequence of numbers.  We now output:

    5 -> 2 [style=solid label="\"Ñùṃéℝô\""]

independently of the user's locale.

* src/system.h (obstack_backslash): New.
* src/graphviz.h, src/graphviz.c (escape): Remove, use
obstack_backslash instead.
* src/print-graph.c: Likewise.
* tests/report.at: Adjust.

1 files changed, 14 insertions, 5 deletions

diff --git a/src/print-graph.c b/src/print-graph.c
index 5691c6d8..adaa8bed 100644
--- a/src/print-graph.c
+++ b/src/print-graph.c
@@ -72,19 +72,28 @@ print_core (struct obstack *oout, state *s)
         obstack_printf (oout, "%*s| ",
                         (int) strlen (previous_lhs->symbol->tag), "");
       else
-        obstack_printf (oout, "%s: ", escape (r->lhs->symbol->tag));
+        {
+          obstack_backslash (oout, r->lhs->symbol->tag);
+          obstack_printf (oout, ": ");
+        }
       previous_lhs = r->lhs;
 
       for (item_number const *sp = r->rhs; sp < sp1; sp++)
-        obstack_printf (oout, "%s ", escape (symbols[*sp]->tag));
+        {
+          obstack_backslash (oout, symbols[*sp]->tag);
+          obstack_1grow (oout, ' ');
+        }
 
       obstack_1grow (oout, '.');
 
       if (0 <= *r->rhs)
         for (item_number const *sp = sp1; 0 <= *sp; ++sp)
-          obstack_printf (oout, " %s", escape (symbols[*sp]->tag));
+          {
+            obstack_1grow (oout, ' ');
+            obstack_backslash (oout, symbols[*sp]->tag);
+          }
       else
-        obstack_printf (oout, " %%empty");
+        obstack_sgrow (oout, " %empty");
 
       /* Experimental feature: display the lookahead tokens. */
       if (report_flag & report_lookahead_tokens
@@ -104,7 +113,7 @@ print_core (struct obstack *oout, state *s)
               BITSET_FOR_EACH (biter, reds->lookahead_tokens[redno], k, 0)
                 {
                   obstack_sgrow (oout, sep);
-                  obstack_sgrow (oout, escape (symbols[k]->tag));
+                  obstack_backslash (oout, symbols[k]->tag);
                   sep = ", ";
                 }
               obstack_1grow (oout, ']');