Feedback cleanup

This patch splits pretty printing representation from IO operations.

- `Pp` is kept in charge of the abstract pretty printing representation.
- The `Feedback` module provides interface for doing printing IO.

The patch continues work initiated for 8.5 and has the following effects:

- The following functions in `Pp`: `pp`, `ppnl`, `pperr`, `pperrnl`,
  `pperr_flush`, `pp_flush`, `flush_all`, `msg`, `msgnl`, `msgerr`,
  `msgerrnl`, `message` are removed. `Feedback.msg_*` functions must be
  used instead.

- Feedback provides different backends to handle output, currently,
  `stdout`, `emacs` and CoqIDE backends are provided.

- Clients cannot specify flush policy anymore, thus `pp_flush` et al are
  gone.

- `Feedback.feedback` takes an `edit_or_state_id` instead of the old
  mix.

Lightly tested: Test-suite passes, Proof General and CoqIDE seem to work.

1 files changed, 2 insertions, 2 deletions

diff --git a/plugins/firstorder/g_ground.ml4 b/plugins/firstorder/g_ground.ml4
index 134b6ba94..a78532e33 100644
--- a/plugins/firstorder/g_ground.ml4
+++ b/plugins/firstorder/g_ground.ml4
@@ -74,7 +74,7 @@ END
 
 VERNAC COMMAND EXTEND Firstorder_Print_Solver CLASSIFIED AS QUERY
 | [ "Print" "Firstorder" "Solver" ] -> [
-    Pp.msg_info
+    Feedback.msg_info
       (Pp.(++) (Pp.str"Firstorder solver tactic is ") (print_default_solver ())) ]
 END
 
@@ -131,7 +131,7 @@ ARGUMENT EXTEND firstorder_using
 | [ "using" reference(a) "," ne_reference_list_sep(l,",") ] -> [ a::l ]
 | [ "using" reference(a) reference(b) reference_list(l) ] -> [
     Flags.if_verbose
-      Pp.msg_warning (Pp.str "Deprecated syntax; use \",\" as separator");
+      Feedback.msg_warning (Pp.str "Deprecated syntax; use \",\" as separator");
     a::b::l
   ]
 | [ ] -> [ [] ]