Simplify

Signed-off-by: Etienne Millon <me@emillon.org>

src/dune_rules/compilation_context.ml

@@ -208,11 +208,10 @@ let create ~super_context ~scope ~expander ~obj_dir ~modules ~flags
   ; loc
   }
 
-let for_alias_module t ?flags alias_module =
+let for_alias_module t ?(keep_flags = false) alias_module =
   let flags =
-    match flags with
-    | Some f -> f
-    | None ->
+    if keep_flags then t.flags
+    else
       let project = Scope.project t.scope in
       let dune_version = Dune_project.dune_version project in
       let profile = (Super_context.context t.super_context).profile in

src/dune_rules/compilation_context.mli

@@ -43,7 +43,7 @@ val create :
   -> t Memo.t
 
 (** Return a compilation context suitable for compiling the alias module. *)
-val for_alias_module : t -> ?flags:Ocaml_flags.t -> Module.t -> t
+val for_alias_module : t -> ?keep_flags:bool -> Module.t -> t
 
 val super_context : t -> Super_context.t
 

src/dune_rules/module_compilation.ml

@@ -486,8 +486,7 @@ let build_all cctx =
             if Modules.is_stdlib_alias modules m then
               (* XXX it would probably be simpler if the flags were just for this
                  module in the definition of the stanza *)
-              let flags = Compilation_context.flags cctx in
-              Compilation_context.for_alias_module cctx m ~flags
+              Compilation_context.for_alias_module cctx m ~keep_flags:true
             else cctx
           in
           build_module cctx m))