Fix oxcaml build compatibility for PR #1400 cherry-pick
- Add missing source_loc_jane fields to Module and ModuleType records
in tools.ml (required by oxcaml's extended Component types)
- Add Strengthen case to is_elidable_with_u pattern matches in
compile.ml and link.ml (oxcaml adds this variant to U.expr)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>