Support exported_post_linker_flags in prebuilt_haskell_library

Summary:
As per other rules, support linker flags to put at the end of
the linkable

Reviewed By: shayne-fletcher

Differential Revision: D58766267

fbshipit-source-id: 6663c4b8e8ae01aac313a08b83d706289824eaff

prelude/decls/haskell_rules.bzl

@@ -232,6 +232,7 @@ haskell_prebuilt_library = prelude_rule(
         } |
         haskell_common.exported_linker_flags_arg() |
         {
+            "exported_post_linker_flags": attrs.list(attrs.arg(anon_target_compatible = True), default = []),
             "contacts": attrs.list(attrs.string(), default = []),
             "cxx_header_dirs": attrs.list(attrs.source(), default = []),
             "db": attrs.source(),

prelude/haskell/haskell.bzl

@@ -284,12 +284,14 @@ def haskell_prebuilt_library_impl(ctx: AnalysisContext) -> list[Provider]:
         link_infos[link_style] = LinkInfos(
             default = LinkInfo(
                 pre_flags = ctx.attrs.exported_linker_flags,
+                post_flags = ctx.attrs.exported_post_linker_flags,
                 linkables = linkables,
             ),
         )
         prof_link_infos[link_style] = LinkInfos(
             default = LinkInfo(
                 pre_flags = ctx.attrs.exported_linker_flags,
+                post_flags = ctx.attrs.exported_post_linker_flags,
                 linkables = prof_linkables,
             ),
         )