fix(pkg): add relocatable-compiler to compiler_package_names

The relocatable-compiler package installs libraries (including threads,
str, unix) under target/lib/ocaml/, matching the layout of other compiler
packages. Without being listed in compiler_package_names, install_roots
did not append the /ocaml subdirectory to its lib_root, causing dev-tools
like utop to fail with "Library threads not found".

Signed-off-by: Ali Caglayan <alizter@gmail.com>

Author: Alizter

src/dune_pkg/dev_tool.ml

@@ -128,7 +128,12 @@ let needs_to_build_with_same_compiler_as_project = function
 let compiler_package_names =
   List.map
     ~f:Package_name.of_string
-    [ "ocaml"; "ocaml-base-compiler"; "ocaml-variants"; "ocaml-compiler" ]
+    [ "ocaml"
+    ; "ocaml-base-compiler"
+    ; "ocaml-variants"
+    ; "ocaml-compiler"
+    ; "relocatable-compiler"
+    ]
 ;;
 
 let is_compiler_package name =