Use compiler-libs' compression for read cmi and cmt files

src/ocaml/compression/dune

@@ -0,0 +1,4 @@
+(library
+ (name ocaml_compression)
+ (public_name merlin-lib.ocaml_compression)
+ (libraries compiler-libs.common))

src/ocaml/compression/ocaml_compression.ml

@@ -0,0 +1,3 @@
+
+(** We rely on [compiler-libs] for compression *)
+include Compression

src/ocaml/typing/cmi_format.ml

@@ -35,7 +35,7 @@ type cmi_infos = {
 }
 
 let input_cmi ic =
-  let (name, sign) = (input_value ic : header) in
+  let (name, sign) = (Ocaml_compression.input_value ic : header) in
   let crcs = (input_value ic : crcs) in
   let flags = (input_value ic : flags) in
   {
@@ -76,7 +76,7 @@ let read_cmi filename =
 let output_cmi filename oc cmi =
 (* beware: the provided signature must have been substituted for saving *)
   output_string oc Config.cmi_magic_number;
-  output_value oc ((cmi.cmi_name, cmi.cmi_sign) : header);
+  Ocaml_compression.output_value oc ((cmi.cmi_name, cmi.cmi_sign) : header);
   flush oc;
   let crc = Digest.file filename in
   let crcs = (cmi.cmi_name, Some crc) :: cmi.cmi_crcs in

src/ocaml/typing/cmt_format.ml

@@ -121,11 +121,11 @@ let clear_env binary_annots =
 
 exception Error of error
 
-let input_cmt ic = (input_value ic : cmt_infos)
+let input_cmt ic = (Ocaml_compression.input_value ic : cmt_infos)
 
 let output_cmt oc cmt =
   output_string oc Config.cmt_magic_number;
-  output_value oc (cmt : cmt_infos)
+  Ocaml_compression.output_value oc (cmt : cmt_infos)
 
 let read filename =
 (*  Printf.fprintf stderr "Cmt_format.read %s\n%!" filename; *)

src/ocaml/typing/dune

@@ -7,4 +7,4 @@
    -open Merlin_utils
    (:standard -w -9))
   (modules_without_implementation annot outcometree)
-  (libraries merlin_utils ocaml_parsing ocaml_utils))
+  (libraries merlin_utils ocaml_compression ocaml_parsing ocaml_utils))