feat(pkg): x build-lib / prebuilt consumption — binary packages end-to-end (#64)

The package-manager half of prebuilt binary packages, on top of the compiler
foundation (dynamic system registration + --emit-module).

- x build-lib [module.ludic]: compile a package's module to a per-target native
  dylib under lib/<target>/, with an @rpath install name so a consumer resolves
  it from the content-addressed store.
- x link-flags: print the clang flags (the dylib, an rpath to its store dir,
  -export_dynamic) so any build system links a project's prebuilt module dylibs;
  x app splices them automatically for in-repo builds.
- kind prebuilt is resolved + linked like any dependency; a missing build target
  stays a hard error.

Proven hermetically (macOS-gated, since dylibs are native): a module exporting a
component + an @System(Update) + a function is built with x build-lib, fetched
as a prebuilt dep, and linked into a consumer game that never saw its source —
the module's system mutates the shared world and its function is callable
("3 42"). Package suite 17/0; full suite 87/0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/x/build.ludic

@@ -62,12 +62,14 @@ function cmd_app() -> int {
   if (src == null) { err("usage: x app <file.ludic> [--headless] [--save-temps]\n"); return 1 }
   let name = capture_line(`basename {src} .ludic`)
 
+  let pbf = prebuilt_link_flags()          # #64: link resolved prebuilt module dylibs, if any
+
   if (mode == 2) {
     let outbin = `build/{name}_headless`
     let ll = `{outbin}.ll`
     print(`ludicc: {src} -> {outbin}  (renders the last frame to build/out.ppm)`)
     if not shq(`bin/ludicc --headless {src} > {ll}`) { return 1 }
-    if not shq(`{cc()} -O2 {ll} -o {outbin}`) { return 1 }
+    if not shq(`{cc()} -O2 {ll}{pbf} -o {outbin}`) { return 1 }
     if not save { run(`rm -f {ll}`) }
     print(`done. run: mkdir -p build && printf 'ddss' | ./{outbin} && open build/out.ppm`)
     return 0
@@ -79,7 +81,7 @@ function cmd_app() -> int {
   if not shq(`bin/ludicc --windowed {src} > {ll}`) { return 1 }
   # audio.ll (#22) is always linked here for the dev runner — unused snd_* are
   # dead-stripped; the canonical `ludicc -o` path links it only when Audio.* is used.
-  if not shq(`{cc()} -O2 {ll} runtime/native/cocoa.ll runtime/native/audio.ll -framework Cocoa -Wl,-needed_framework,GameController -Wl,-needed_framework,AVFoundation -Wl,-rpath,@loader_path -o {outbin}`) { return 1 }
+  if not shq(`{cc()} -O2 {ll} runtime/native/cocoa.ll runtime/native/audio.ll -framework Cocoa -Wl,-needed_framework,GameController -Wl,-needed_framework,AVFoundation -Wl,-rpath,@loader_path{pbf} -o {outbin}`) { return 1 }
   if not save { run(`rm -f {ll}`) }
   print(`done. run: ./{outbin}   (from the repo root, so assets/ resolves)`)
   return 0

tools/x/main.ludic

@@ -43,6 +43,8 @@ program X {
     print("  x update [module]             bump a dep (or all) to its latest published version, then relock")
     print("  x verify                      check every locked package against the store by content hash")
     print("  x vendor                      copy the resolved packages into ./vendor for offline builds")
+    print("  x build-lib <module.ludic>    (#64) compile a package's module to a prebuilt dylib in lib/<target>/")
+    print("  x link-flags                  (#64) print the clang flags to link this project's prebuilt module dylibs")
     print("")
     print("test:")
     print("  x test                        the full regression suite")
@@ -121,6 +123,8 @@ program X {
     if (cmd == "update") { exit(cmd_pkg_update()) }
     if (cmd == "verify") { exit(cmd_pkg_verify()) }
     if (cmd == "vendor") { exit(cmd_pkg_vendor()) }
+    if (cmd == "build-lib") { exit(cmd_pkg_build_lib()) }
+    if (cmd == "link-flags") { exit(cmd_pkg_link_flags()) }
     if (cmd == "test-pkg") { exit(cmd_test_pkg()) }
     if (cmd == "version") or (cmd == "--version") or (cmd == "-v") { exit(cmd_version()) }
     if (cmd == "release") { exit(cmd_release()) }

tools/x/pkg.ludic

@@ -638,6 +638,77 @@ function cmd_pkg_vendor() -> int {
   return 0
 }
 
+# ---- prebuilt binary packages (issue #64) -----------------------------------
+
+# x build-lib [module.ludic] — compile a package's module to a prebuilt dylib for
+# the current target, under lib/<target>/. The developer runs this in the package
+# repo, commits the artifact, and `git tag`s — consumers fetch and link it.
+# The compiler is $LUDICC (default bin/ludicc) so this works both in-repo and,
+# with the flag set, from an installed toolchain.
+function cmd_pkg_build_lib() -> int {
+  var src = argn(2, "")
+  if src == "" { src = capture_line("ls *.ludic 2>/dev/null | grep -v package.ludic | head -1") }
+  if src == "" or not file_exists(src) { err("usage: x build-lib <module.ludic>  (run in the package directory)\n");  return 1 }
+  let man = read_root_manifest()
+  var name = ""
+  if man.module != "" { name = capture_line(`basename {man.module}`) }
+  if name == "" { name = capture_line(`basename {src} .ludic`) }
+  let t = target_id()
+  run(`mkdir -p lib/{t}`)
+  let ludicc = getenv_or("LUDICC", "bin/ludicc")
+  let ll = "/tmp/x_buildlib.ll"
+  if not shq(`{ludicc} --emit-module {src} -o {ll} 2>/tmp/x_bl.err`) {
+    err(`x: build-lib compile failed — {capture_line("tail -1 /tmp/x_bl.err")}\n`);  return 1
+  }
+  let out = `lib/{t}/lib{name}.dylib`
+  # @rpath install name so a consumer resolves it via -rpath to the store dir
+  if not shq(`{cc()} -O2 -Wno-override-module -dynamiclib -undefined dynamic_lookup -Wl,-install_name,@rpath/lib{name}.dylib {ll} -o {out} 2>/tmp/x_bl.err`) {
+    err(`x: build-lib link failed — {capture_line("tail -1 /tmp/x_bl.err")}\n`);  return 1
+  }
+  run(`rm -f {ll}`)
+  print(`built {out}  (target {t})`)
+  print(`add to package.ludic:  kind prebuilt  /  targets "{t}"  — then commit lib/ and git tag`)
+  return 0
+}
+
+# x link-flags — print the clang link flags a consumer build needs to pull in the
+# project's prebuilt module dylibs (for the current target). Portable escape from
+# `x app` (which is in-repo only): any build system can splice `$(x link-flags)`
+# into its link step.
+function cmd_pkg_link_flags() -> int {
+  let f = prebuilt_link_flags()
+  print(s_trim(f))
+  return 0
+}
+
+# clang link flags that pull every locked prebuilt package's dylib (for the
+# current target) into a consumer build: the dylib itself, an rpath to its store
+# directory, and -export_dynamic so the module resolves the host's ludic_* ABI at
+# load. Empty when the project has no prebuilt dependencies.
+function prebuilt_link_flags() -> pointer {
+  let txt = read_file("package.lock.ludic")
+  if txt == null { return "" }
+  let locked = parse_lock(txt)
+  let t = target_id()
+  var flags = ""
+  var any = false
+  var i = 0
+  while i < len(locked) {
+    let m = locked[i]
+    if m.kind == "prebuilt" {
+      let raw = strip_prefix(m.hash, "sha256:")
+      let dir = `{store_root()}{raw}/lib/{t}`
+      let libs = split_lines(capture(`ls {dir}/*.dylib 2>/dev/null`))
+      var k = 0
+      while k < len(libs) { flags = flags + " " + libs[k];  any = true;  k = k + 1 }
+      if len(libs) > 0 { flags = flags + ` -Wl,-rpath,{dir}` }
+    }
+    i = i + 1
+  }
+  if any { flags = flags + " -Wl,-export_dynamic" }
+  return flags
+}
+
 # drop a leading `prefix` from `s` if present
 function strip_prefix(s: pointer, prefix: pointer) -> pointer {
   let pn = slen(prefix)

tools/x/pkg_test.ludic

@@ -170,5 +170,41 @@ function cmd_test_pkg() -> int {
     ok("x vendor copies the resolved packages into ./vendor")
   } else { bad2("x vendor failed", capture_line(`tail -1 {work}/vendor.out`)) }
 
+  # ---- prebuilt binary package (issue #64): exported function + system + component
+  # A module is compiled to a dylib (x build-lib), fetched as a `kind prebuilt`
+  # dependency, and linked into a consumer game that never saw its source. At load
+  # the module registers a dynamic component and an @System(Update); the consumer
+  # also calls an exported function via `extern`. Native/dylib only → macOS-gated.
+  if not is_darwin() {
+    skip("prebuilt binary packages (dylib) — native/macOS only")
+    return report()
+  }
+  let tgt = `native-{capture_line("uname -m")}`
+  let mp = `{proxy}/example.test/manapack`
+  run(`mkdir -p {mp} && git -C {mp} init -q`)
+  pt_write(`{mp}/package.ludic`, `package "example.test/manapack"` + nl() + `version "1.0.0"` + nl() + "kind prebuilt" + nl() + `provides "Mana"` + nl() + `targets "{tgt}"` + nl())
+  pt_write(`{mp}/manapack.ludic`, "program ManaPack {\n  function module_init() -> void { world_register_prop(\"Mana\", 2) }\n  @System(Update) function mana_regen() -> void {\n    let M = world_prop_id(\"Mana\")\n    let e = world_query_next(M, 0)\n    if e >= 0 { let v = world_get(e, M, 0); world_set(e, M, 0, v + 1) }\n  }\n  function mana_bonus() -> int { return 42 }\n}\n")
+  if shq(`( cd {mp} && LUDICC={root}/bin/ludicc {root}/bin/x build-lib manapack.ludic > {work}/bl.out 2>&1 )`) and file_exists(`{mp}/lib/{tgt}/libmanapack.dylib`) {
+    ok("x build-lib compiles a package module to a per-target dylib")
+  } else { bad2("x build-lib failed", capture_line(`tail -1 {work}/bl.out`)) }
+  pt_commit_tag(mp, "v1.0.0")
+
+  let proj3 = `{work}/proj3`
+  pt_write(`{proj3}/package.ludic`, `package "game"` + nl() + `version "0.0.0"` + nl() + `require "example.test/manapack" "1.0.0"` + nl())
+  pt_write(`{proj3}/game.ludic`, "program Game {\n  property Dummy { x: int = 0 }\n  model Ent { Dummy }\n  @OnSpawn(Ent) handler Init { }\n  extern function mana_bonus() -> int = \"fn_mana_bonus\"\n  var frames: int = 0\n  handler Boot phase Start {\n    let e = world_spawn(world_model_id(\"Ent\"))\n    let M = world_prop_id(\"Mana\")\n    world_attach_dyn(e, M)\n    world_set(e, M, 0, 0)\n  }\n  handler Run phase Update {\n    frames = frames + 1\n    if frames >= 4 {\n      let M = world_prop_id(\"Mana\")\n      let e = world_query_next(M, 0)\n      print(world_get(e, M, 0))\n      print(mana_bonus())\n      quit()\n    }\n  }\n}\n")
+  if shq(`( cd {proj3} && {envp} {root}/bin/x get > {work}/get3.out 2>&1 )`) and file_exists(`{proj3}/ludic_modules/example.test/manapack/lib/{tgt}/libmanapack.dylib`) {
+    ok("x get fetches + links a prebuilt (kind prebuilt) package for the target")
+  } else { bad2("prebuilt x get failed", capture_line(`tail -1 {work}/get3.out`)) }
+  # compile the ECS consumer from the repo root (so runtime/native resolves), then
+  # link the module dylib via `x link-flags` (a real external build's link step).
+  run(`LUDIC_HOME={root} {root}/bin/ludicc --headless {proj3}/game.ludic --emit-llvm -o {proj3}/game.ll 2>{work}/gc.err`)
+  let flags = capture_line(`( cd {proj3} && LUDIC_STORE={store} {root}/bin/x link-flags )`)
+  if shq(`{cc()} -O2 -Wno-override-module {proj3}/game.ll {flags} -o {proj3}/game 2>{work}/gl.err`) {
+    let got = capture_line(`printf 'aaaaaa' | {proj3}/game`)
+    if got == "3 42" {
+      ok("a consumer links the prebuilt module: its system mutates the world + its function is callable (\"3 42\")")
+    } else { bad2("prebuilt consumer output mismatch", `got [{got}] want [3 42]`) }
+  } else { bad2("prebuilt consumer link failed", capture_line(`tail -1 {work}/gl.err`)) }
+
   return report()
 }