Merge branch 'js/maintenance-fix-deadlock-on-win10' into maint-2.54

To help Windows 10 installations, avoid removing files whose
contents are still mmap()'ed.

* js/maintenance-fix-deadlock-on-win10:
  maintenance(geometric): do release the `.idx` files before repacking
  mingw: optionally use legacy (non-POSIX) delete semantics