[log] exporting tty mode for channels

src/kernel_services/plugin_entry_points/log.ml

@@ -804,6 +804,7 @@ sig
     ('a,formatter,unit) format -> 'a
 
   val result  : ?level:int -> ?dkey:category -> 'a pretty_printer
+  val has_tty : unit -> bool
   val feedback: ?ontty:ontty -> ?level:int -> ?dkey:category -> 'a pretty_printer
   val debug   : ?level:int -> ?dkey:category -> 'a pretty_printer
   val warning : ?wkey: warn_category -> 'a pretty_printer
@@ -1038,6 +1039,8 @@ struct
 
   let transient channel = channel.terminal.isatty && !tty ()
 
+  let has_tty () = transient channel
+
   let feedback
       ?(ontty=`Message)
       ?(level=1) ?dkey ?current ?source

src/kernel_services/plugin_entry_points/log.mli

@@ -158,6 +158,9 @@ module type Messages = sig
       @since Beryllium-20090601-beta1
       @see <https://frama-c.com/download/frama-c-plugin-development-guide.pdf> Plug-in Development Guide *)
 
+  val has_tty : unit -> bool
+  (** Returns [true] is this Log's channel is in console mode *)
+
   val feedback : ?ontty:ontty -> ?level:int -> ?dkey:category -> 'a pretty_printer
   (** Progress and feedback. Level is tested against the verbosity level.
       @since Beryllium-20090601-beta1