Revert "Revert PMP's fix of #2498, which introduces an incompatibility with lablgtk"

This reverts commit 469cb750c6c1aa46f77b2a89a36f79f29aa97073.

1 files changed, 41 insertions, 9 deletions

diff --git a/configure.ml b/configure.ml
index 47721f778..b8bb650b1 100644
--- a/configure.ml
+++ b/configure.ml
@@ -670,10 +670,18 @@ let operating_system, osdeplibs =
 
 (** * lablgtk2 and CoqIDE *)
 
+type source = Manual | OCamlFind | Stdlib
+
+let get_source = function
+| Manual -> "manually provided"
+| OCamlFind -> "via ocamlfind"
+| Stdlib -> "in OCaml library"
+
 (** Is some location a suitable LablGtk2 installation ? *)
 
-let check_lablgtkdir ?(fatal=false) msg dir =
+let check_lablgtkdir ?(fatal=false) src dir =
   let yell msg = if fatal then die msg else (printf "%s\n" msg; false) in
+  let msg = get_source src in
   if not (dir_exists dir) then
     yell (sprintf "No such directory '%s' (%s)." dir msg)
   else if not (Sys.file_exists (dir/"gSourceView2.cmi")) then
@@ -687,11 +695,11 @@ let check_lablgtkdir ?(fatal=false) msg dir =
 let get_lablgtkdir () =
   match !Prefs.lablgtkdir with
   | Some dir ->
-    let msg = "manually provided" in
+    let msg = Manual in
     if check_lablgtkdir ~fatal:true msg dir then dir, msg
-    else "", ""
+    else "", msg
   | None ->
-    let msg = "via ocamlfind" in
+    let msg = OCamlFind in
     let d1,_ = tryrun "ocamlfind" ["query";"lablgtk2.sourceview2"] in
     if d1 <> "" && check_lablgtkdir msg d1 then d1, msg
     else
@@ -699,10 +707,34 @@ let get_lablgtkdir () =
       let d2,_ = tryrun "ocamlfind" ["query";"lablgtk2"] in
       if d2 <> "" && d2 <> d1 && check_lablgtkdir msg d2 then d2, msg
       else
-        let msg = "in OCaml library" in
+        let msg = Stdlib in
         let d3 = camllib^"/lablgtk2" in
         if check_lablgtkdir msg d3 then d3, msg
-        else "", ""
+        else "", msg
+
+(** Detect and/or verify the Lablgtk2 version *)
+
+let check_lablgtk_version src dir = match src with
+| Manual | Stdlib ->
+  let test accu f =
+    if accu then
+      let test = sprintf "grep -q -w %s %S/glib.mli" f dir in
+      Sys.command test = 0
+    else false
+  in
+  let heuristics = [
+    "convert_with_fallback";
+    "wrap_poll_func"; (** Introduced in lablgtk 2.16 *)
+  ] in
+  let ans = List.fold_left test true heuristics in
+  if ans then printf "Warning: could not check the version of lablgtk2.\n";
+  (ans, "an unknown version")
+| OCamlFind ->
+  let v, _ = tryrun "ocamlfind" ["query"; "-format"; "%v"; "lablgtk2"] in
+  try
+    let vi = List.map s2i (numeric_prefix_list v) in
+    ([2; 16] <= vi, v)
+  with _ -> (false, v)
 
 let pr_ide = function No -> "no" | Byte -> "only bytecode" | Opt -> "native"
 
@@ -726,9 +758,9 @@ let check_coqide () =
   if !Prefs.coqide = Some No then set_ide No "CoqIde manually disabled";
   let dir, via = get_lablgtkdir () in
   if dir = "" then set_ide No "LablGtk2 not found";
-  let found = sprintf "LablGtk2 found (%s)" via in
-  let test = sprintf "grep -q -w convert_with_fallback %S/glib.mli" dir in
-  if Sys.command test <> 0 then set_ide No (found^" but too old");
+  let (ok, version) = check_lablgtk_version via dir in
+  let found = sprintf "LablGtk2 found (%s, %s)" (get_source via) version in
+  if not ok then set_ide No (found^", but too old (required >= 2.16, found " ^ version ^ ")");
   (* We're now sure to produce at least one kind of coqide *)
   lablgtkdir := shorten_camllib dir;
   if !Prefs.coqide = Some Byte then set_ide Byte (found^", bytecode requested");