Nix devshell build broken

[edolstra]

Describe the bug

Nix master (31f3f23) fails to build for me:

# nix develop 
# autoreconfPhase
# configurePhase
# installPhase
install flags: -j24 SHELL=/nix/store/5jw69mbaj5dg4l2bj58acg3gxywfszpj-bash-5.2p26/bin/bash profiledir=\$\(out\)/etc/profile.d PRECOMPILE_HEADERS=1 sysconfdir=\$\(out\)/etc install
...
  GEN    /home/eelco/Dev/nix-master/outputs/out/share/doc/nix/manual/index.html
error: File not found: ../store/types/
   ┌─ release-notes/rl-next.md:60:197
   │
60 │   The build hook protocol did in principle support custom ways of remote building, but that can also be accomplished with a custom service for the ssh or daemon/ssh-ng protocols, or with a custom [store type](../store/types/) i.e. `Store` subclass. <!-- we normally don't mention classes, but consider that this release note is about a library use case -->
   │                                                                                                                                                                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File not found: ../store/types/

Error: One or more incorrect links
2024-08-16 19:41:56 [ERROR] (mdbook::renderer): Renderer exited with non-zero return code.
2024-08-16 19:41:56 [ERROR] (mdbook::utils): Error: Rendering failed
2024-08-16 19:41:56 [ERROR] (mdbook::utils):    Caused By: The "linkcheck" renderer failed
make: *** [doc/manual/local.mk:215: /home/eelco/Dev/nix-master/outputs/out/share/doc/nix/manual/index.html] Error 101

Also, installCheckPhase gives weird errors, e.g.

    umount: /tmp/nix-shell.RjTsff/nix-test/local-overlay-store/delete-refs/stores/merged-store/nix/store: filesystem was unmounted, but failed to update userspace mount table.
make: *** [mk/lib.mk:93: tests/functional/local-overlay-store/delete-refs.sh.test] Error 16

Finally, checkPhase no longer does anything (#11301).

Steps To Reproduce

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Expected behavior

A clear and concise description of what you expected to happen.

nix-env --version output

Additional context

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