os-path causes build conflict with unix_ffi os

Building fails for the unix port when adding the glob package to the variant manifest with:

require("glob", unix_ffi=True)

glob's manifest requires os-path, without unix_ffi, and that in turns requires os also without unix_ffi:

require("os", unix_ffi=True)
require("os-path")

os-path's manifest requires os:

require("os")
package("os")

This causes a conflict with the os that has already been required with unix_ffi:

build-standard/frozen_content.c:20526:27: error: redefinition of ‘const_qstr_table_data_os___init__’
20526 | static const qstr_short_t const_qstr_table_data_os___init__[158] = {
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
build-standard/frozen_content.c:17919:27: note: previous definition of ‘const_qstr_table_data_os___init__’ was here
17919 | static const qstr_short_t const_qstr_table_data_os___init__[158] = {
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
....

If I add unix_ffi=True to lib/micropython-lib/python-stdlib/os-path/manifest.py, then it is able to compile the frozen content.

Start with lib/micropython-lib/python-stdlib/os-path/manifest.py and compare its os requirement with the unix port requirements shown in the issue. Reproduce the unix build with glob in the variant manifest and verify that the frozen content no longer contains duplicate os definitions.