Uncommon: remove unused failwith

rng/entropy.ml

@@ -120,7 +120,7 @@ let cpu_rng_bootstrap =
   | Some insn ->
     let cpu_rng_bootstrap id =
       let r = cpu_rng insn () in
-      if r = 0 then failwith "bad CPU RNG value";
+      if r = 0 then failwith "Mirage_crypto_rng.Entropy: 0 is a bad CPU RNG value";
       let buf = Bytes.create 10 in
       Bytes.set_int64_le buf 2 (Int64.of_int r);
       write_header id buf;

src/mirage_crypto.mli

@@ -38,7 +38,6 @@ module Uncommon : sig
   val xor_into : string -> src_off:int -> bytes -> dst_off:int -> int -> unit
 
   val invalid_arg : ('a, Format.formatter, unit, unit, unit, 'b) format6 -> 'a
-  val failwith : ('a, Format.formatter, unit, unit, unit, 'b) format6 -> 'a
 end
 
 (**/**)

src/uncommon.ml

@@ -4,7 +4,6 @@ let kasprintf k fmt =
   Format.(kfprintf (fun _ -> k (flush_str_formatter ())) str_formatter fmt)
 
 let invalid_arg fmt = kasprintf invalid_arg ("Mirage_crypto: " ^^ fmt)
-let failwith fmt = kasprintf failwith ("Mirage_crypto: " ^^ fmt)
 
 let (//) x y =
   if y < 1 then raise Division_by_zero else