Compiler: Build_info/Unit_info: conversion to and from string maps (#1657)

Co-authored-by: Jérôme Vouillon <[email protected]>

Author: OlivierNicole

compiler/lib/build_info.ml

@@ -90,6 +90,10 @@ let parse s =
       in
       Some t
 
+let to_map : t -> string StringMap.t = Fun.id
+
+let of_map : string StringMap.t -> t = Fun.id
+
 exception
   Incompatible_build_info of
     { key : string

compiler/lib/build_info.mli

@@ -34,6 +34,10 @@ val to_string : t -> string
 
 val parse : string -> t option
 
+val to_map : t -> string StringMap.t
+
+val of_map : string StringMap.t -> t
+
 val with_kind : t -> kind -> t
 
 exception