pkg-config: use dontUnpack instead of no-op phase

[alyssais]

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[AndersonTorres]

Anyone can verify if this splices correctly?

[alyssais]

From what I remember I did quite a bit of cross testing with this. Note that the only change to splicing here is moving away from it for targetPrefix.

[ghost]

Anyone can verify if this splices correctly?

Yes, it does.

I cross compile the whole userspace of my mips routers from my much-faster powerpc builders.

I did that build at this PR and it successfully cross-compiled the following referrers of these two (glibc and musl) cross-targeted pkg-configs:

PC_GLIBC=/nix/store/fg3mzwz4nc7z65zy2v1cjff61l82wix2-mips64el-unknown-linux-gnuabi64-pkg-config-wrapper-0.29.2.drv
PC_MUSL=/nix/store/jsafg4dq0d9gcm1c2d8qz1ag37vr2wv1-mips64el-unknown-linux-muslabi64-pkg-config-wrapper-0.29.2.drv
for A in $(( \
  nix-store -q --referrers $PC_GLIBC; \
  nix-store -q --referrers $PC_MUSL \
) | sort | uniq | xargs -L1 nix-store -q)
do test -e $A && echo $A
done

List of successfully cross-compiled outpaths

/nix/store/1zh40xkh7l1livd2h662d924hm7ld8da-curl-mips64el-unknown-linux-gnuabi64-7.87.0-devdoc
/nix/store/5v6zf8hk34mq13ggzm3af3mksz2im7nv-curl-mips64el-unknown-linux-gnuabi64-7.87.0-man
/nix/store/apb0xw9wbyy3cl3qfvcy5fx0y62d729a-curl-mips64el-unknown-linux-gnuabi64-7.87.0-debug
/nix/store/glq9ss2ggl0s37i47b729lvp83pn3ni9-curl-mips64el-unknown-linux-gnuabi64-7.87.0-dev
/nix/store/r1138wrv7bl83qyzvh3qq3rbq7yjxw3y-curl-mips64el-unknown-linux-gnuabi64-7.87.0
/nix/store/rn5xqspsv9a8qr8i9jlknl0pl8bralf6-curl-mips64el-unknown-linux-gnuabi64-7.87.0-bin
/nix/store/1kc22jdjijpppgkj1ir50g5hf9sij5gb-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1-debug
/nix/store/9v6sblcvg9byyhfqc9gkvrrmk40m62jr-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1-man
/nix/store/adhbjwa1sv1rlnfq352xzhhkiqqm7hjw-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1-bin
/nix/store/dvmycx2a7qghy97jjbkhp2r5323p4x0y-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1
/nix/store/mgd8hkpmpfqi5r93m0dkh7kaq8vxp2qi-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1-lib
/nix/store/zh0idgi8hqz0y9qdqmqg1kqmh5prqih2-util-linux-minimal-mips64el-unknown-linux-gnuabi64-2.38.1-dev
/nix/store/29rm3pqsq424h9w25k3ldmglzqxxp7d2-nghttp2-static-mips64el-unknown-linux-muslabi64-1.51.0-dev
/nix/store/5hpvc0djyp57by614d32jgsyhn7adh7x-nghttp2-static-mips64el-unknown-linux-muslabi64-1.51.0-bin
/nix/store/8bjm90653yjv8awgxmh2kb1mz18gxvjn-nghttp2-static-mips64el-unknown-linux-muslabi64-1.51.0-lib
/nix/store/pnjrgrgh52lfshw9vsgj6ri7jcc4ir5c-nghttp2-static-mips64el-unknown-linux-muslabi64-1.51.0
/nix/store/0j7lc18idx1z1rh5j3f3g379glzdj6v3-systemd-minimal-mips64el-unknown-linux-gnuabi64-252.4-dev
/nix/store/n5q95zxyslpvwdhfbv6zah9s7jrnmrsc-systemd-minimal-mips64el-unknown-linux-gnuabi64-252.4-man
/nix/store/zyk2b2mqcgz8kk41i3awvnyrc3jm3adh-systemd-minimal-mips64el-unknown-linux-gnuabi64-252.4
/nix/store/5fbanyxqfzm7jal79af3d8py29xb6q96-kmod-mips64el-unknown-linux-gnuabi64-30-lib
/nix/store/5s3nwzfcns6cdmwx8pw5gzh1kb8065il-kmod-mips64el-unknown-linux-gnuabi64-30
/nix/store/j9n6svfwf2v8jzrh29mz3hm4x30p4kfa-kmod-mips64el-unknown-linux-gnuabi64-30-dev
/nix/store/1iaardzn8fwsz7rcxh7rxgadsqcy8y56-tpm2-tss-mips64el-unknown-linux-gnuabi64-3.2.0
/nix/store/5fp46c4sgck3l1n42x6jzqkbkcfyna38-pcsclite-mips64el-unknown-linux-gnuabi64-1.9.5-bin
/nix/store/6gxi3ipb9i7yjz286c8k5vpnpsjwymlp-pcsclite-mips64el-unknown-linux-gnuabi64-1.9.5-man
/nix/store/x4yhzwch4jjvalyyvzgxv1syyk9wn68q-pcsclite-mips64el-unknown-linux-gnuabi64-1.9.5-doc
/nix/store/xzqy6rvjzy4610c798hfyp070mxj8nfg-pcsclite-mips64el-unknown-linux-gnuabi64-1.9.5
/nix/store/zzaj6v6bfm3c48s8qh9wmq9di0j10g3k-pcsclite-mips64el-unknown-linux-gnuabi64-1.9.5-dev
/nix/store/7flr9qs3rcjcav5rmhpgclzms8h39x3m-gnutls-mips64el-unknown-linux-gnuabi64-3.7.8-bin
/nix/store/80fw4iqzq1bndm3iashzxkv3fbhxh5km-gnutls-mips64el-unknown-linux-gnuabi64-3.7.8-dev
/nix/store/85k3im8z5qq4v30k92jfdp9frkwlnm66-gnutls-mips64el-unknown-linux-gnuabi64-3.7.8
/nix/store/la0ym0c17cy87d7nmxqjsilw6zjqbpyg-gnutls-mips64el-unknown-linux-gnuabi64-3.7.8-devdoc
/nix/store/nyqgja1r9dqwxf8izgbr800rk3l88pa8-gnutls-mips64el-unknown-linux-gnuabi64-3.7.8-man
/nix/store/pc8qf9j723zcs2a6x70shvnzwhfcw4n4-libbpf-mips64el-unknown-linux-gnuabi64-1.1.0
/nix/store/059kxi3ism0nidcz1sx4idf9ndlm7k2g-libfido2-mips64el-unknown-linux-gnuabi64-1.12.0
/nix/store/062157187dk37b2qvnqdjd2hmjwwl4ja-libfido2-mips64el-unknown-linux-gnuabi64-1.12.0-man
/nix/store/jzcxr0vdwci871np8q2qpzypqkh5q31a-libfido2-mips64el-unknown-linux-gnuabi64-1.12.0-dev
/nix/store/glbkyhhj3r6malwbsp4srw77hqy8h8qh-unbound-mips64el-unknown-linux-gnuabi64-1.17.0-lib
/nix/store/k1qs94i3pfv8lgvgxf8zhx738z844q5x-unbound-mips64el-unknown-linux-gnuabi64-1.17.0-man
/nix/store/zrahqyxxxrp5gkq0r0qjprflqn87ck39-unbound-mips64el-unknown-linux-gnuabi64-1.17.0
/nix/store/30iv85k8jwnaz8a97h7pbnxc752kq393-p11-kit-mips64el-unknown-linux-gnuabi64-0.24.1-dev
/nix/store/7x2rlx6d41k2r3avycdk7ajw7yq12yim-p11-kit-mips64el-unknown-linux-gnuabi64-0.24.1-bin
/nix/store/vpy6sxs5wln7a770s9hh9yd705300qw5-p11-kit-mips64el-unknown-linux-gnuabi64-0.24.1
/nix/store/p0hxch2v3a30swb1h29fl5mbws54rx4d-kbd-mips64el-unknown-linux-gnuabi64-2.5.1
/nix/store/5dq1rbfqf6zanw1g7x88kxvw0rjylzfr-libxml2-static-mips64el-unknown-linux-muslabi64-2.10.3-dev
/nix/store/fznsdjbvnp1ibpazjqpw57zyzzy4zkbb-libxml2-static-mips64el-unknown-linux-muslabi64-2.10.3-bin
/nix/store/mxb1idmg504and0vhzkm6hrxxaxxpzq9-libxml2-static-mips64el-unknown-linux-muslabi64-2.10.3-doc
/nix/store/nva818s59x5rxjp19j09wqv6752c5c04-libxml2-static-mips64el-unknown-linux-muslabi64-2.10.3
/nix/store/k7r25yqnyxp99gyn71phh8mv1kilr1ma-ncurses-mips64el-unknown-linux-gnuabi64-6.4-dev
/nix/store/nzagv9lamcg8bcaxqqgphrijg9pnd131-ncurses-mips64el-unknown-linux-gnuabi64-6.4-man
/nix/store/yydmr5zvj9p73p04ac4xzm9h28ray76w-ncurses-mips64el-unknown-linux-gnuabi64-6.4
/nix/store/2djipggdp0r4plw9j8qy63sx200gwzrh-iptables-mips64el-unknown-linux-gnuabi64-1.8.8
/nix/store/62h2fljwybaa7jiv9lrij740r4ciadky-iptables-mips64el-unknown-linux-gnuabi64-1.8.8-man
/nix/store/jsv22927l7vil7jni8sslar5rykwddy1-iptables-mips64el-unknown-linux-gnuabi64-1.8.8-dev
/nix/store/29kfqyvxbhyxf64xam90g3wmp2ji6vz8-python3-mips64el-unknown-linux-gnuabi64-3.10.9
/nix/store/4fpiambi8yaswm8dqnq7sl56nm95q4ba-python3-mips64el-unknown-linux-gnuabi64-3.10.9-debug
/nix/store/cbhsl81pz6sz96jwabbd33xapfk0557g-libmicrohttpd-mips64el-unknown-linux-gnuabi64-0.9.71-devdoc
/nix/store/dxzxc3da8nn6ybfx6gnpq0mxzjjbzj9s-libmicrohttpd-mips64el-unknown-linux-gnuabi64-0.9.71-dev
/nix/store/hf2s4mvkf458jz3b1lgpvl97mh4k29wd-libmicrohttpd-mips64el-unknown-linux-gnuabi64-0.9.71
/nix/store/jq6gr6n0y5qi5m0jifjiqii8am1cshn4-libmicrohttpd-mips64el-unknown-linux-gnuabi64-0.9.71-info
/nix/store/lmg1bf4qkjfm1ykz3q6vi2a73wirshah-libapparmor-mips64el-unknown-linux-gnuabi64-3.1.2
/nix/store/r401dcda3h72p9khq25mcsbsc30jr7s6-libnftnl-mips64el-unknown-linux-gnuabi64-1.2.4
/nix/store/36sgwgmrywpi03wkpglr77j098djv8lh-nghttp2-mips64el-unknown-linux-gnuabi64-1.51.0-dev
/nix/store/3fa581kac6c5dbsbis2vfvdi8mc5a4n8-nghttp2-mips64el-unknown-linux-gnuabi64-1.51.0-bin
/nix/store/47746dn126wgqs1sj4vclmk8w1q1if6w-nghttp2-mips64el-unknown-linux-gnuabi64-1.51.0-lib
/nix/store/zbsxsl8ipd8kxn43snjmvw7br0w1h37b-nghttp2-mips64el-unknown-linux-gnuabi64-1.51.0
/nix/store/6pwh5k5nb62ahbz5cwg19ly9z46jw9a1-tcb-mips64el-unknown-linux-gnuabi64-1.2
/nix/store/7rz5n8xiagl2mbn6ghg38az4p65v4wwg-tcb-mips64el-unknown-linux-gnuabi64-1.2-man
/nix/store/mn8zgcif6wfa6zp311pkq6a3yh4z0d8z-tcb-mips64el-unknown-linux-gnuabi64-1.2-dev
/nix/store/wyag8h8s15gf2kcn2j7x7v5903yivfgf-tcb-mips64el-unknown-linux-gnuabi64-1.2-bin
/nix/store/6rqvk5k84v8f2kyd8910r0aml8fbgvfh-lvm2-mips64el-unknown-linux-gnuabi64-2.03.18-man
/nix/store/b2zbwqnb953wr8c5aajf7q2hl9f0fzab-lvm2-mips64el-unknown-linux-gnuabi64-2.03.18-dev
/nix/store/by3nmi6l68b30n5cnr54bb8z48p8xva5-lvm2-mips64el-unknown-linux-gnuabi64-2.03.18-lib
/nix/store/iswm3fqsy8hfaq76ic69aklignvflakr-lvm2-mips64el-unknown-linux-gnuabi64-2.03.18-bin
/nix/store/kgr39lc5xsr8x4w1ar6rhqn1j38vph8c-lvm2-mips64el-unknown-linux-gnuabi64-2.03.18
/nix/store/mzqn0ayk0xlldrf2m2c7kaq36ivmyr5w-gnupg-mips64el-unknown-linux-gnuabi64-2.3.7
/nix/store/njg9bkc41bjfscv2hk5v953m42nglpbh-libkrb5-mips64el-unknown-linux-gnuabi64-1.20.1-dev
/nix/store/scyd57cr2ca4gg9lhqrbpvq5jgf3fhxm-libkrb5-mips64el-unknown-linux-gnuabi64-1.20.1
/nix/store/3x56q6yam278myyybcx1fkgln755h9dr-cryptsetup-mips64el-unknown-linux-gnuabi64-2.5.0-debug
/nix/store/5im82anzpp5nxxwhjmgy8xc5izdpyszl-cryptsetup-mips64el-unknown-linux-gnuabi64-2.5.0-man
/nix/store/63mmlq9c96cx0gl504y58myy0yc26am9-cryptsetup-mips64el-unknown-linux-gnuabi64-2.5.0-dev
/nix/store/alx041capjbalnpf0c9q65yqjjy55ash-cryptsetup-mips64el-unknown-linux-gnuabi64-2.5.0
/nix/store/y7v7nf18vmqb32cdc5wpgv09gm90y17b-cryptsetup-mips64el-unknown-linux-gnuabi64-2.5.0-bin
/nix/store/2q8pp2ih0w5npw35f66w58hqyqi533y0-libnetfilter_conntrack-mips64el-unknown-linux-gnuabi64-1.0.9

... before failing for reasons totally unrelated to this PR. I have fixed those unrelated reasons and restarted the build; it should be done by morning. But if you're looking for a "smoke test" the above should be plenty; there's no need to wait for it.

The unrelated reason

systemd doesn't build on mips via nixpkgs right now. Some BPF header wackery, ~~I think it's~~ it is in fact the same issue as [this](https://github.com//pull/194149); cherry-picking that got past `libsystemd` and built `tor`. I cherry-picked the rest of my local customizations (including the "without systemd" patch) and restarted the build, but it'll be a global rebuild.

[Ericson2314]

This is not wrong, but I am in general wary of referring to targetPackages when it is not strictly necessary? Even if this doesn't cause splicing issues today, it could down the road if e.g. if things in the bootstrap are made to use pkg-config instead of ad-hoc methods.

[alyssais]

Fine, I've dropped that commit.