Build nix-store with Meson

Special thanks to everyone that has worked on a Meson port so far,
@p01arst0rm and @Qyriad in particular.

Co-Authored-By: p01arst0rm <polar@ever3st.com>
Co-Authored-By: Artemis Tosini <lix@artem.ist>
Co-Authored-By: Artemis Tosini <me@artem.ist>
Co-Authored-By: Felix Uhl <felix.uhl@outlook.com>
Co-Authored-By: Jade Lovelace <lix@jade.fyi>
Co-Authored-By: Lunaphied <lunaphied@lunaphied.me>
Co-Authored-By: Maximilian Bosch <maximilian@mbosch.me>
Co-Authored-By: Pierre Bourdon <delroth@gmail.com>
Co-Authored-By: Qyriad <qyriad@qyriad.me>
Co-Authored-By: Rebecca Turner <rbt@sent.as>
Co-Authored-By: Winter <winter@winter.cafe>
Co-Authored-By: eldritch horrors <pennae@lix.systems>
Co-Authored-By: jade <lix@jade.fyi>
Co-Authored-By: julia <midnight@trainwit.ch>
Co-Authored-By: rebecca “wiggles” turner <rbt@sent.as>
Co-Authored-By: wiggles dog <rbt@sent.as>
Co-Authored-By: fricklerhandwerk <valentin@fricklerhandwerk.de>
Co-authored-by: Eli Schwartz <eschwartz93@gmail.com>

flake.nix

@@ -169,6 +169,17 @@
               ;
           };
 
+          nix-store = final.callPackage ./src/libstore/package.nix {
+            inherit
+              fileset
+              stdenv
+              officialRelease
+              versionSuffix
+              ;
+            libseccomp = final.libseccomp-nix;
+            busybox-sandbox-shell = final.busybox-sandbox-shell or final.default-busybox-sandbox-shell;
+          };
+
           nix =
             final.callPackage ./package.nix {
               inherit
@@ -260,6 +271,7 @@
         {
           "nix" = { };
           "nix-util" = { };
+          "nix-store" = { };
         }
         // lib.optionalAttrs (builtins.elem system linux64BitSystems) {
         dockerImage =
@@ -312,10 +324,11 @@
               "${(pkgs.formats.yaml { }).generate "pre-commit-config.yaml" modular.pre-commit.settings.rawConfig}";
           };
 
-          inherit (pkgs.nix-util) mesonFlags;
+          mesonFlags = pkgs.nix-util.mesonFlags ++ pkgs.nix-store.mesonFlags;
 
           nativeBuildInputs = attrs.nativeBuildInputs or []
             ++ pkgs.nix-util.nativeBuildInputs
+            ++ pkgs.nix-store.nativeBuildInputs
             ++ [
               modular.pre-commit.settings.package
               (pkgs.writeScriptBin "pre-commit-hooks-install"