Revert "Revert ocaml#7415 and ocaml#7450 (ocaml#7887)"

This reverts commit 886df09.

CHANGES.md

@@ -26,9 +26,6 @@ Unreleased
 - The `interface` and `implementation` fields of a `(dialect)` are now optional
   (#7757, @gpetiot)
 
-- Revert #7415 and #7450 (Resolve `ppx_runtime_libraries` in the target context when
-  cross compiling) (#7887, fixes #7875, @emillon)
-
 3.8.0 (2023-05-23)
 ------------------
 
@@ -85,7 +82,7 @@ Unreleased
 - Fix `dune install` when cross compiling (#7410, fixes #6191, @anmonteiro,
   @rizo)
 
-- Find `pps` dependencies in the host context when cross-compiling,  (#7415,
+- Find `pps` dependencies in the host context when cross-compiling,  (#7410,
   fixes #4156, @anmonteiro)
 
 - Dune in watch mode no longer builds concurrent rules in serial (#7395

src/dune_rules/buildable_rules.ml

@@ -56,9 +56,8 @@ let modules_rules ~preprocess ~preprocessor_deps ~lint
         (Preprocess.Per_module.instrumentation_deps preprocess
            ~instrumentation_backend)
     in
-    Preprocessing.make sctx ~dir ~scope
-      ~preprocess:preprocess_with_instrumentation ~expander ~preprocessor_deps
-      ~instrumentation_deps ~lint ~lib_name
+    Preprocessing.make sctx ~dir ~preprocess:preprocess_with_instrumentation
+      ~expander ~preprocessor_deps ~instrumentation_deps ~lint ~lib_name
   in
   let add_empty_intf =
     let default = empty_module_interface_if_absent in

src/dune_rules/cinaps.ml

@@ -120,7 +120,7 @@ let gen_rules sctx t ~dir ~scope =
     Preprocessing.make sctx ~dir ~expander
       ~lint:(Preprocess.Per_module.no_preprocessing ())
       ~preprocess:t.preprocess ~preprocessor_deps:t.preprocessor_deps
-      ~instrumentation_deps:[] ~lib_name:None ~scope
+      ~instrumentation_deps:[] ~lib_name:None
   in
   let* modules =
     Modules.singleton_exe module_

src/dune_rules/expander.ml

@@ -65,6 +65,8 @@ type t =
 
 let scope t = t.scope
 
+let scope_host t = t.scope_host
+
 let artifacts t = t.bin_artifacts_host
 
 let dir t = t.dir

src/dune_rules/expander.mli

@@ -6,6 +6,8 @@ type t
 
 val scope : t -> Scope.t
 
+val scope_host : t -> Scope.t
+
 val dir : t -> Path.Build.t
 
 val context : t -> Context.t

src/dune_rules/jsoo/jsoo_rules.ml

@@ -355,7 +355,7 @@ let setup_separate_compilation_rules sctx components =
     let pkg = Lib_name.parse_string_exn (Loc.none, s_pkg) in
     let ctx = Super_context.context sctx in
     let open Memo.O in
-    let* installed_libs = Lib.DB.installed ctx in
+    let* installed_libs = Lib.DB.installed ~host:None ctx in
     Lib.DB.find installed_libs pkg >>= function
     | None -> Memo.return ()
     | Some pkg ->