Add (alias_rec ...) in dependency specification

(alias_rec XXX) means the same as @XXX on the command line.

src/jbuild.ml

@@ -200,6 +200,7 @@ module Dep_conf = struct
   type t =
     | File of String_with_vars.t
     | Alias of String_with_vars.t
+    | Alias_rec of String_with_vars.t
     | Glob_files of String_with_vars.t
     | Files_recursively_in of String_with_vars.t
 
@@ -211,6 +212,7 @@ module Dep_conf = struct
       sum
         [ cstr "file"                 (fun x -> File x)
         ; cstr "alias"                (fun x -> Alias x)
+        ; cstr "alias_rec"            (fun x -> Alias_rec x)
         ; cstr "glob_files"           (fun x -> Glob_files x)
         ; cstr "files_recursively_in" (fun x -> Files_recursively_in x)
         ]
@@ -226,6 +228,8 @@ module Dep_conf = struct
       List [Atom "file" ; String_with_vars.sexp_of_t t]
     | Alias t ->
       List [Atom "alias" ; String_with_vars.sexp_of_t t]
+    | Alias_rec t ->
+      List [Atom "alias_rec" ; String_with_vars.sexp_of_t t]
     | Glob_files t ->
       List [Atom "glob_files" ; String_with_vars.sexp_of_t t]
     | Files_recursively_in t ->

src/jbuild.mli

@@ -93,6 +93,7 @@ module Dep_conf : sig
   type t =
     | File of String_with_vars.t
     | Alias of String_with_vars.t
+    | Alias_rec of String_with_vars.t
     | Glob_files of String_with_vars.t
     | Files_recursively_in of String_with_vars.t
 

src/super_context.ml

@@ -410,11 +410,14 @@ module Deps = struct
     | File  s ->
       let path = Path.relative dir (expand_vars t ~scope ~dir s) in
       Build.path path
-      >>^ fun _ -> [path]
+      >>^ fun () -> [path]
     | Alias s ->
-      let path = Alias.file (Alias.make ~dir (expand_vars t ~scope ~dir s)) in
-      Build.path path
-      >>^ fun _ -> []
+      Alias.dep (Alias.make ~dir (expand_vars t ~scope ~dir s))
+      >>^ fun () -> []
+    | Alias_rec s ->
+      Alias.dep_rec ~loc:(String_with_vars.loc s) ~file_tree:t.file_tree
+        (Alias.make ~dir (expand_vars t ~scope ~dir s))
+      >>^ fun () -> []
     | Glob_files s -> begin
         let path = Path.relative dir (expand_vars t ~scope ~dir s) in
         match Glob_lexer.parse_string (Path.basename path) with