Review findings from the pilot: the 17-module default import set was
maintained twice (root's array and build-support's userBinary) — drift
would silently make packaged binaries differ from root-built ones. It
now lives once, as build-support.defaultImports; root and userBinary
both draw from it, and root's user-binary wrapper names the shim +
link script through the kernel package like build-support does.
The root aggregate test step likewise duplicated the library domains'
14 test definitions; it now depends on each domain's own standalone
test step (host-only, so root's -Dtarget/-Doptimize deliberately do
not reach them), and the client domain gains an empty test step for
uniformity. Boot-image file list unchanged.
build-support gains the domains-based userBinary: the default import set
(the library/kernel concern modules, driver/service clients, mmio,
acpi-ids, xkeyboard-config) is assembled from the domain packages, and
the root shim + user link script come from the kernel package directory.
system/drivers/pci-bus is the first binary package: a ~15-line
declarative build.zig naming only its extras (device-manager-protocol,
pci-class); the root build consumes the artifact for the boot image and
the driver also builds standalone from its own directory. Boot-image
file list unchanged.
The shared user-binary recipe (freestanding target, root-shim wiring,
link-script and image-base settings) moves out of the root build into
build-support/, the package that is the single home for cross-cutting
build changes (docs/build-packages-plan.md). The root build's
addUserBinary/addThreadedUserBinary keep their signatures and delegate;
nothing else moves. Boot-image file list unchanged.
Daniel Samson