deb/cross: stop exporting PKG_CONFIG_LIBDIR for cross builds

dpkg-buildpackage and sbuild export no pkg-config redirection: the
environment is the package's to set.  Pointing the whole build at the
target multiarch pkgconfig dirs makes every pkg-config-consuming tool
resolve against the target libraries, the host-side tools of the same
build included: the host linker is then handed target-arch -L paths
(the kernel's resolve_btfids logging 'skipping incompatible
/usr/lib/aarch64-linux-gnu/libelf.so') and only survives through
fallbacks when the build-architecture libraries happen to be installed
too.

Packages whose cross builds need target pkg-config data must arrange
for it themselves, the way the kernel packaging builds rtla statically
against no target system libraries.

.github/workflows/ci.yml

@@ -138,7 +138,7 @@ jobs:
     - name: Set up container image
       run: |
         apt-get update
-        apt-get install -y nodejs sudo curl wget ca-certificates
+        apt-get install -y nodejs sudo curl wget ca-certificates build-essential
     - uses: actions/checkout@v6
     - uses: dtolnay/rust-toolchain@stable
     - name: Install build dependencies

README.md

@@ -6,7 +6,13 @@
 
 ## Installation
 
-No distribution channel is published yet; build from source:
+From crates.io:
+
+```
+cargo install pkh
+```
+
+Or build from source (the same system packages are needed either way):
 
 ```
 sudo apt install pkg-config libssl-dev libgpg-error-dev libgpgme-dev

data/quirks.yml

@@ -15,18 +15,38 @@ quirks:
   # against the host architecture, whose dependency closure conflicts with
   # the `:native` python3. Resolve it against the build architecture
   # until the control is fixed upstream.
+  # The resolute and stonking kernels declare the host-tool libraries
+  # unqualified (libelf-dev for resolve_btfids, libdw-dev for
+  # gendwarfksyms, libssl-dev for sign-file), unlike the Debian control,
+  # which carries the same names qualified `:native`.  The dpkg cross
+  # rules resolve an unqualified Multi-Arch: same name against the host
+  # architecture only, so a cross build installs no build-architecture
+  # variants and the kernel's host-side tools cannot link.  Inject the
+  # build-architecture variants until the control is fixed upstream.
   linux:
     deb:
       - series: [resolute]
         dependencies:
           replace:
             llvm-21-dev: llvm-21-dev:native <!stage1>
+      - series: [resolute, stonking]
+        dependencies:
+          inject:
+            - libelf-dev:native
+            - libdw-dev:native
+            - libssl-dev:native
   linux-riscv:
     deb:
       - series: [resolute]
         dependencies:
           replace:
             llvm-21-dev: llvm-21-dev:native <!stage1>
+      - series: [resolute, stonking]
+        dependencies:
+          inject:
+            - libelf-dev:native
+            - libdw-dev:native
+            - libssl-dev:native
 
   # Add more packages and their quirks as needed
   # example-package:

data/skill/SKILL.md

@@ -0,0 +1,130 @@
+---
+name: pkh
+description: 'Drive pkh, a Debian/Ubuntu packaging helper: pull source packages, generate changelog entries, build .dsc/.deb, lint, and upload to a PPA. Use it whenever the task touches Debian or Ubuntu packaging: patching an existing package, preparing an SRU, backport or NMU, scaffolding a new .deb, rebuilding for a PPA, or uploading a source package. Trigger on "update the changelog", "package this", or a bare package name, even when the user never mentions Debian.'
+---
+
+# pkh
+
+`pkh` wraps the Debian packaging toolchain (`dch`, `dpkg-buildpackage`,
+`sbuild`, `dpkg-source`, `quilt`, `lintian`, PPA uploads) in one CLI.
+The subcommands share one set of option names, so `-s` always targets
+the series and `--ppa` always names the PPA. Each step also does more
+than the raw tool it replaces: `pull` fetches the orig tarball with the
+source, `chlog` commits the entry it writes, `deb` sets up a chroot and
+installs the build dependencies.
+
+Check the install with `pkh --version`. Each command lists its flags
+with `pkh <command> --help`, so check there instead of guessing. pkh
+shells out to host tools (git, dpkg-dev, quilt, mmdebstrap, lintian,
+pristine-tar, schroot, ...). Install the ones your workflow uses, or
+use the classic snap, which carries them.
+
+## Shared options
+
+| Option | Meaning |
+|---|---|
+| `-d, --dist <dist>` | Target distribution, `debian` or `ubuntu` |
+| `-s, --series <series>` | Target series, for example `resolute` or `noble` |
+| `-v, --version <version>` | Target package version |
+| `-a, --arch <arch>` | Target architecture, for example `amd64` or `riscv64` |
+| `-p, --pocket <pocket>` | Distribution pocket: `updates`, `security`, `proposed` |
+| `--ppa <user/ppa>` | Act on the named PPA |
+
+Defaults come from the host vendor, its development series, and its
+architecture. When the target differs, pass the flags: packaging for
+Ubuntu on a Debian host needs `-d ubuntu`, and a series or architecture
+that differs from the host needs `-s` or `-a`.
+
+## Patch an Ubuntu package
+
+```
+pkh pull hello                     # source and orig tarball; add -d ubuntu off an Ubuntu host
+# edit the package, committing each patch to git
+pkh chlog                          # generates the entry, opens it for editing, commits it
+git add debian/changelog && git commit -m "d/changelog"
+pkh build                          # source package, written next to the tree
+pkh deb                            # binary build in a chroot with build deps installed
+pkh lint                           # lintian plus pkh-native checks
+pkh put --ppa user/hello_xxx       # uploads the .changes file from the build
+git push xxx user-fork             # push the branch to your fork
+```
+
+Run `pkh chlog` and `pkh build` from the root of the source tree; they
+act on the package in the current directory.
+
+## Command reference
+
+- `pkh new [name]` scaffolds a buildable source package. `--lang`
+  picks the build system (`rust`, `python`, `meson`, `cmake`,
+  `autotools`, `go`, `shell`, `makefile`); `--source <PATH>` packages
+  existing sources instead. `--upstream-version` and `--revision` set
+  the version. `--description`, `--homepage`, `--license <SPDX>`,
+  `--command`, `--maintainer "Name <email>"`, and `--depends` fill in
+  the package metadata, with the maintainer defaulting to
+  `DEBFULLNAME`/`DEBEMAIL` and then git config. `--quilt` and
+  `--native` choose the source format; `--orig-from
+  release|git|path|snapshot` and `--orig-path` control the orig
+  tarball. The changelog starts as `UNRELEASED`; `--release` targets
+  `--series` instead. `--defaults` answers every remaining question
+  with its default, which keeps the run non-interactive.
+
+- `pkh pull <package>` fetches a source package from the archive or
+  git. `--archive` skips git. `--ppa user/ppa` and `--repository
+  <suite-url>` pull from a PPA or an external flat repository instead.
+  `-d`, `-s`, `-v`, and `-p` target an exact source.
+
+- `pkh chlog` generates the changelog entry from the commits since the
+  last version tag, opens it for editing, and commits it. `--backport`,
+  `--nmu`, and `--rebuild` apply the matching numbering scheme
+  (`3.1-1ubuntu2~24.04.1`, `1.0-1.1`, `1.0-1build1`); `-v` sets an
+  explicit version instead.
+
+- `pkh build` produces the .dsc. `--orig auto|always|never` controls
+  whether the upload includes the orig tarball; the default, `auto`,
+  includes it only when the upstream version changed.
+
+- `pkh deb` builds the binary packages in an isolated context with the
+  build dependencies installed. `--ppa` (repeatable) adds dependency
+  sources, `--inject <package|.deb>` preinstalls a package, and `-j`
+  caps parallel jobs. `--cross` cross-compiles instead of using
+  qemu-binfmt, but most packages cannot cross-compile, so prefer qemu.
+  Leave `--mode` unset unless you need a specific build context.
+
+- `pkh lint [path]` runs lintian plus the pkh-native checks. `--json`
+  emits a machine-readable report and `--list-tags` prints the native
+  tag catalog. `--fail-on` sets the severities that fail the run
+  (errors by default), `--suppress-tags` ignores tags, `--check` runs a
+  single native check, and `--info`, `--pedantic`, and
+  `--experimental` add detail. `--repack` packs the tree fresh instead
+  of reusing the existing build output.
+
+- `pkh put [changes]` uploads a .changes file to `--ppa user/ppa`.
+  With no argument it uploads the .changes from this package's last
+  build, found next to the source tree. `--force` re-uploads a file
+  that was already uploaded.
+
+- `pkh prune` removes build artifacts and caches. Run it with
+  `--dry-run` first to list them. `--all` also deletes the cached
+  chroot tarballs, which take long to download again, so use it when
+  you need the disk space.
+
+## Notes for agent runs
+
+- Pass `-d`, `-s`, and `-a` whenever the target differs from the host,
+  so runs are reproducible.
+- Keep runs non-interactive. Pass explicit flags, use `pkh new
+  --defaults`, and set `EDITOR` before `pkh chlog` (`EDITOR=true` keeps
+  the generated text). Commands may ask short questions on the
+  terminal; flags avoid most prompts.
+- Pass `RUST_LOG=debug` for pkh's own logs. `--verbose` on `pkh build`
+  and `pkh deb` prints raw tool output instead of the live view.
+- pkh writes the build artifacts (.dsc, .changes, logs) next to the
+  source tree. `pkh put` finds them without arguments, and `pkh prune`
+  removes them again.
+- Run `pkh lint` before `pkh put`. It exits nonzero when findings reach
+  the `--fail-on` level, which defaults to errors.
+- pkh intercepts Ctrl+C, runs its cleanup hooks, and exits with status
+  130. `pkh prune` removes anything left over.
+
+The upstream repository is https://git.vhaudiquet.fr/vhaudiquet/pkh.
+Its README has longer workflow examples.

src/deb/cross.rs

@@ -62,20 +62,6 @@ pub fn setup_environment(
         .map_err(|e| format!("Invalid UTF-8 in dpkg-architecture output: {e}"))?;
     parse_dpkg_architecture_output(&dpkg_architecture, env);
 
-    // In-tree tools locate their libraries with the *host* pkg-config during
-    // cross builds (the kernel's tools/build feature checks derive their
-    // cflags/ldflags from `pkg-config --cflags/--libs`), whose search path
-    // only covers the build architecture's pkgconfig dirs. Point it at the
-    // target's so `libtraceevent` & co resolve to target-arch libraries:
-    // linux-riscv cross builds die in rtla's Makefile.config otherwise, even
-    // with the target -dev packages installed.
-    if let Some(multiarch) = env.get("DEB_HOST_MULTIARCH").cloned() {
-        env.insert(
-            "PKG_CONFIG_LIBDIR".to_string(),
-            format!("/usr/lib/{multiarch}/pkgconfig:/usr/share/pkgconfig"),
-        );
-    }
-
     env.insert("DEB_BUILD_PROFILES".to_string(), "cross".to_string());
 
     Ok(())
@@ -304,21 +290,18 @@ mod tests {
         assert!(cross_suites("noble", None, "not-a-distro").is_err());
     }
 
-    /// setup_environment exports the target multiarch pkg-config libdir:
-    /// tools' feature checks run the *host* pkg-config, which must find the
-    /// target's .pc files (rtla hard-errors on libtraceevent otherwise,
-    /// failing linux-riscv cross builds despite the target -dev packages
-    /// being installed).
+    /// setup_environment exports the dpkg cross variables and the 'cross'
+    /// build profile, and nothing beyond what dpkg-buildpackage exports:
+    /// no pkg-config redirection (the environment is the package's to
+    /// set, and target-arch pkgconfig paths would also poison the
+    /// host-side tools of the same build).
     #[test]
-    fn test_setup_environment_exports_cross_pkg_config_libdir() {
+    fn test_setup_environment_exports_dpkg_cross_variables_only() {
         let mut env = HashMap::new();
         let ctx = Arc::new(Context::new(crate::context::ContextConfig::Local).unwrap());
         setup_environment(&mut env, "riscv64", ctx).unwrap();
 
-        assert_eq!(
-            env.get("PKG_CONFIG_LIBDIR").map(String::as_str),
-            Some("/usr/lib/riscv64-linux-gnu/pkgconfig:/usr/share/pkgconfig")
-        );
+        assert!(!env.contains_key("PKG_CONFIG_LIBDIR"));
         assert_eq!(
             env.get("DEB_BUILD_PROFILES").map(String::as_str),
             Some("cross")

src/deb/local.rs

@@ -1154,6 +1154,39 @@ mod tests {
         assert_eq!(spec, "t:amd64");
     }
 
+    /// Cross parity with dpkg's checker and sbuild's apt-resolved dummy
+    /// package: an unqualified Multi-Arch: same name resolves to the
+    /// host-architecture variant even when a build-architecture candidate
+    /// exists — the build-architecture side is only ever installed
+    /// through an explicit `:native` declaration (or a pkh quirk
+    /// injecting one), never alongside the host variant.
+    #[test]
+    fn install_spec_unqualified_same_package_never_dual_installs() {
+        let host = "arm64";
+        let build = "amd64";
+
+        let spec = install_spec_for(
+            &rel("t"),
+            &[cand("amd64", "same"), cand("arm64", "same")],
+            build,
+            host,
+        )
+        .unwrap();
+        assert_eq!(spec, "t:arm64");
+
+        // The build-architecture side comes from `:native` declarations:
+        // the co-installable build-arch variant of the same source
+        // package.
+        let spec = install_spec_for(
+            &rel("t:native"),
+            &[cand("amd64", "same"), cand("arm64", "same")],
+            build,
+            host,
+        )
+        .unwrap();
+        assert_eq!(spec, "t:amd64");
+    }
+
     /// Qualified dependencies install exactly the variant their qualifier
     /// selects per dpkg semantics; virtual names (no candidates) pass
     /// through unqualified for apt to resolve a provider.

src/quirks.rs

@@ -265,15 +265,62 @@ mod tests {
     fn linux_dependency_quirks_are_series_scoped() {
         for package in ["linux", "linux-riscv"] {
             let rules = get_deb_dependency_quirks(package, "resolute");
-            assert_eq!(rules.len(), 1, "the resolute entry applies");
+            assert_eq!(rules.len(), 2, "the resolute entries apply");
             assert_eq!(
                 rules[0].replace.get("llvm-21-dev").map(String::as_str),
                 Some("llvm-21-dev:native <!stage1>")
             );
+            // Only the stonking entry exists there: the llvm-21-dev
+            // replacement above is a resolute-only packaging state.
+            let rules = get_deb_dependency_quirks(package, "stonking");
+            assert_eq!(rules.len(), 1);
+            assert!(rules[0].replace.is_empty());
             assert!(get_deb_dependency_quirks(package, "noble").is_empty());
         }
     }
 
+    /// The kernels of the series whose control dropped the Debian-style
+    /// `:native` qualifiers on the host-tool libraries inject the
+    /// build-architecture variants: the dpkg cross rules resolve the
+    /// unqualified Multi-Arch: same names against the host architecture
+    /// only, leaving nothing for the kernel's host-side tools to link.
+    #[test]
+    fn linux_injects_native_host_tool_libraries_for_cross() {
+        for series in ["resolute", "stonking"] {
+            let mut clauses = vec![vec![parse("libelf-dev <!stage1>")]];
+            crate::quirks::apply_dependency_quirks("linux", series, &mut clauses, &opts()).unwrap();
+            let injected: Vec<&PkgRelation> = clauses[1..]
+                .iter()
+                .flatten()
+                .filter(|rel| {
+                    ["libelf-dev", "libdw-dev", "libssl-dev"].contains(&rel.package.as_str())
+                })
+                .collect();
+            assert_eq!(
+                injected.len(),
+                3,
+                "one :native clause per host-tool library"
+            );
+            assert!(
+                injected
+                    .iter()
+                    .all(|rel| rel.arch_qualifier.as_deref() == Some("native"))
+            );
+            // The declared dependency itself is untouched: the host
+            // (target) variant still installs for the checker.
+            assert_eq!(clauses[0][0].arch_qualifier, None);
+        }
+    }
+
+    /// Other kernel series keep their declared dependencies untouched.
+    #[test]
+    fn noble_linux_dependencies_are_not_rewritten() {
+        let mut clauses = vec![vec![parse("libelf-dev")]];
+        crate::quirks::apply_dependency_quirks("linux", "noble", &mut clauses, &opts()).unwrap();
+        assert_eq!(clauses.len(), 1);
+        assert_eq!(clauses[0][0].arch_qualifier, None);
+    }
+
     /// `replace` rewrites exactly the dependencies whose declared name
     /// matches, wholesale: the replacement carries its own qualifier and
     /// restrictions.