With every consumer migrated (C2), nothing imports `runtime` or `system` any
longer. Removed both shim files and their build.zig module definitions, dropped
the `runtime` entry from `default_imports`, and rewrote the per-binary root shim
(library/kernel/root.zig) to import `start` (_start + panic) and `logging`
(std_options) directly instead of through `runtime`.
addUserBinary/addThreadedUserBinary/addUserBinaryImpl lose their `runtime_module`
parameter; the root module now pulls the two modules it needs out of
`default_imports` via a small findImport helper.
The runtime dumping ground is gone: the userspace library is library/kernel
(concern modules), library/device (driver/pci/usb/block/model/mmio/acpi data),
library/client (display, input service clients), and library/protocol (wire
contracts). Consumers @import concern modules by name.
Verified: zig build, zig build test, and QEMU (smoke, thread-spawn, thread-mutex,
logger, display-native, device-manager, usb-storage, input).
The one giant `runtime` module (with a `system.zig` that was itself a dumping
ground of unrelated syscalls) is split into directly-importable, flat concern
modules under library/kernel/:
system-call ipc memory process thread time logging file-system service start
(+ the device/service clients: device, device-manager, block, display, input)
system.zig is dissolved — its functions moved to their concern home (mmap ->
memory, spawn/kill/exit -> process, sleep/clock -> time, write/klog -> logging,
fs* -> file-system). `memory` merges heap+dma+shared-memory behind one flat API
(memory.allocator/dmaAlloc/sharedCreate/mmap), keeping heap's state and malloc
export single. The memory<->thread dependency cycle (heap needs Thread.Mutex,
thread needs mmap) is broken by having thread allocate its own stack via the raw
mmap syscall, so the module graph is a DAG.
This is the atomic step: all 42 internal cross-imports flip from relative to
module imports at once. `runtime.zig` and `system.zig` become thin re-export
SHIMS so the ~38 consumers keep compiling on `runtime.*` untouched; they migrate
to direct imports in C2, after which the shims are deleted (C5).
zig build + zig build test green; 14 QEMU cases pass (smoke, process,
process-kill, thread-spawn/join, logger, vfs, fat-mount, display-native,
usb-storage, virtio-gpu, device-manager, input, power-button).
First step of splitting the runtime dumping ground. Pure directory rename
(git mv library/runtime library/kernel) + the six build.zig path references
repointed. The module is still named "runtime" for now; the next commits split
it into concern modules (ipc, memory, process, time, logging, file-system, ...),
dissolve system.zig, and delete the runtime aggregator.
The library/kernel name follows the kernel32 model: it is the userspace library
that wraps the private kernel ABI, distinct from system/kernel/ (the kernel).
zig build green.
Daniel Samson