nix busybox shell: fix config and enable expected features

[dtzWill]

Fixes known build failures stemming from /bin/sh not
having expected features.

Most of these are enabling POSIX features, but not all.

Resulting busybox grows from 120K -> 140K which seems reasonable.

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[dtzWill]

@dezgeg (and anyone else): this shell has resolved all of the build failures (and annoying extra newlines in "configure" output haha) that I've seen. Please LMK if you find any others! Hopefully this matter is resolved 👍.

[edolstra]

@dtzWill The busybox shell build now fails with:

/build/busybox-1.28.0/scripts/generate_BUFSIZ.sh: line 56: syntax error: you disabled math support for $((arith)) syntax
make: *** [Makefile:857: include/config/MARKER] Error 2
make: *** Waiting for unfinished jobs....

[dezgeg]

So you need to build it with an old Nix which lacks the busybox thing completely then? :P

[dtzWill]

Yes, that's not the fault of this PR but rather the underlying problem this fixes.

(And the awkwardness of even getting back to a good state once you start using the limited busybox shell is part of why I was so eager to see this fixed)

[dezgeg]

Got this:

../include/install-sh -o 1000 -g 100 -m 755 -d /nix/store/fpk1kslcfrn653rh0aqas7dx843ikm0g-attr-2.4.47-bin/bin
../include/install-sh: line 152: getopts: not found
cp: invalid option -- 'o'
Try 'cp --help' for more information.
make[1]: *** [Makefile:32: install] Error 1
make[1]: Leaving directory '/build/attr-2.4.47/attr'
make: *** [Makefile:101: attr-install] Error 2
builder for '/nix/store/1dbzbv563zgb1x21r9gwry5d95236qf2-attr-2.4.47.drv' failed with exit code 2
cannot build derivation '/nix/store/rb05g9y44y13f7vnsnffs8r34xsamhqv-acl-2.2.52.drv': 1 dependencies couldn't be built

[dtzWill]

@dezgeg details?

Sounds like you're running into the sort of problem that motivated this, see the start of a table I made about failures encountered in packages: NixOS/nix#1832 (comment)

Good news is some amount of latest-all-the-things should fix things for you.

[dezgeg]

Ah, I see it's already in that table. This was on the community aarch64 box and I was under the impression that Nix already got updated once but apparently still not new enough. It's running nix-env (Nix) 2.0pre5889_c287d731.

[dtzWill]

That's new enough but I think NixOS needs to be equally new....

Anyway, I can confirm the busybox on the aarch64 community builder isn't fixed yet:

$ nix-store -q --references $(which nix)|grep busy
/nix/store/mrbj338a1j2y712mgkyis9v4gpcd5qk7-busybox-1.28.0

[dtz@nixos:~]$ nix log /nix/store/mrbj338a1j2y712mgkyis9v4gpcd5qk7-busybox-1.28.0|grep GETOPT
[0.0 MiB DL]
getopt (5.6 kb) (GETOPT) [Y/n/?] (NEW) n
  getopts builtin (ASH_GETOPTS) [Y/n] (NEW) n
getopt (5.6 kb) (GETOPT) [N/y/?] n
  getopts builtin (ASH_GETOPTS) [N/y] n
getopt (5.6 kb) (GETOPT) [N/y/?] n
  getopts builtin (ASH_GETOPTS) [N/y] n

[dtz@nixos:~]$ 

vs locally (fixed):

$ nix log $(nix-store -q --references $(which nix)|grep busy)|grep GETOPT
getopt (5.6 kb) (GETOPT) [Y/n/?] (NEW) n
  getopts builtin (ASH_GETOPTS) [Y/n] (NEW) n
getopt (5.6 kb) (GETOPT) [N/y/?] n
  getopts builtin (ASH_GETOPTS) [N/y] n
parseconfig: removing CONFIG_ASH_GETOPTS
parseconfig: setting CONFIG_ASH_GETOPTS=y
getopt (5.6 kb) (GETOPT) [N/y/?] n
  getopts builtin (ASH_GETOPTS) [Y/n] y

(these commands are a bit brittle but hopefully you get the idea :))