Replace the 'dpkg-buildpackage -S' wrapper with a native pipeline in
src/build/:
- deb822 control parser/writer with dpkg-compatible multiline rendering
(control.rs)
- md5/sha1/sha256 checksum registry, insertion-ordered like dpkg's
artifact accumulation (checksums.rs)
- Debian version splitting/validation and full changelog entry parsing,
including binNMU binary-only entries (metadata.rs)
- build-type bitflags and rules-target/artifact-suffix mapping
(buildtype.rs)
- environment setup: SOURCE_DATE_EPOCH, DEB_BUILD_OPTIONS,
dpkg-architecture env dump, vendor default profiles and the sanitized
Environment field recorded in .buildinfo (env.rs)
- debian/files registry with atomic saves (files.rs)
- native .buildinfo writer, including the Installed-Build-Depends
closure computed over the dpkg status database (buildinfo.rs)
- native .changes writer emitting dpkg's canonical field order with
legacy Files + Checksums-Sha1/Sha256 (changes.rs)
- gpgme clearsigning with the transitive checksum cascade
(dsc -> buildinfo -> changes), key discovery from the changelog
maintainer and UNRELEASED no-sign handling (sign.rs)
dpkg-source (-b/--before-build/--after-build) intentionally remains a
subprocess; debian/rules execution is unchanged.
Validated differentially against real dpkg-buildpackage -S -I -i -nc -d
on native and 3.0 (quilt) fixture packages: .dsc byte-identical, .changes
payload matches modulo machine-dependent Installed-Build-Depends and
Environment content, all signatures verify with gpg, artifact ordering
and UNRELEASED no-sign behavior match dpkg.
