fix: 最后一个厂商 SDK 的 include —— <pthread.h> 在这个系统上会赢过图里的那份

    …/MacOSX.sdk/usr/include/mach/mach_time.h:61:1:
      error: a type specifier is required for all declarations     (× 19)

在**这个系统上**构建本包、而目标侧来自依赖图时,SDK 的 <pthread.h> 赢过了图里 C
库的那份,并拉进一个自身前提没有到位的 Mach 头。从 Linux 宿主出发的同一次构建取到
的是图里那份,一声不吭 —— 所以这是宿主差异,只在这里才现形。

⭐ 而本包的其余部分早就不这样做:pthread_create_from_mach_thread 一直是自己声明的
(因为没有头声明它)。openkal-linux 写系统调用号,openkal-opensbi 写 SBI 标识,
openkal-windows 写 Win32 声明 —— 这三个普通名字是最后一处例外。

⭐ pthread_t 在两个 C 库上都是指针(musl 的 struct __pthread*、这个系统的
struct _opaque_pthread_t*),所以 void* 在 ABI 这一层是同一个参数,而 extern "C"
匹配的正是这一层。值在两种情况下都以整数存放。

本机复验:从 Linux 交叉到 aarch64-macos 仍然产出 Mach-O。

Author: speak-agent

src/task.cpp

@@ -22,14 +22,39 @@
 // and the default --- there is no such constraint and the ordinary names are
 // used, which also avoids the cost the other arrangement pays.
 
-#ifndef OKM_STANDALONE
-#include <pthread.h>
-#endif
-
+// ⚠️ DECLARED, NOT INCLUDED — AND THAT IS THE SAME RULE THE BRANCH BELOW
+// ALREADY FOLLOWS.
+//
+// `pthread_create_from_mach_thread` has always been declared here rather than
+// taken from a header, because no header declares it. The three ordinary names
+// were taken from `<pthread.h>`, and that header is this system's SDK — the one
+// thing every other implementation in this ecosystem avoids: openkal-linux
+// writes the system-call numbers, openkal-opensbi the SBI identifiers,
+// openkal-windows the Win32 declarations.
+//
+// ⚠️ Measured 2026-08-23, building this package ON this system with the target
+// side coming from the graph:
+//
+//     …/MacOSX.sdk/usr/include/mach/mach_time.h:61:1:
+//       error: a type specifier is required for all declarations   (× 19)
+//
+// The SDK's `<pthread.h>` won the search over the C library's in the graph, and
+// pulled in a Mach header that its own prerequisites were not there for. On a
+// Linux host the same build had taken the graph's copy and said nothing, which
+// is why the difference is a HOST difference and shows up only here.
+//
+// ⭐ `pthread_t` IS A POINTER ON BOTH C LIBRARIES — `struct __pthread*` in musl
+// and `struct _opaque_pthread_t*` on this system — so `void*` is the same
+// argument at the ABI, which is the level `extern "C"` matches at. The value is
+// stored as an integer below in either case.
 extern "C" {
 #ifdef OKM_STANDALONE
 int pthread_create_from_mach_thread(void** thread, const void* attr,
                                     void* (*start)(void*), void* arg);
+#else
+int pthread_create(void** thread, const void* attr,
+                   void* (*start)(void*), void* arg);
+int pthread_join(void* thread, void** value);
 #endif
 }
 
@@ -83,7 +108,7 @@ int kal_task_start(void (*entry)(void*), void* arg, kal_task* out) {
     void* thread = nullptr;
     const int rc = pthread_create_from_mach_thread(&thread, nullptr, run, c);
 #else
-    pthread_t id{};
+    void* id = nullptr;
     const int rc = ::pthread_create(&id, nullptr, run, c);
     if (rc == 0) c->thread = static_cast<unsigned long>(reinterpret_cast<okm_uptr>(id));
 #endif
@@ -105,7 +130,8 @@ int kal_task_join(kal_task h) {
                  reinterpret_cast<okm_long>(const_cast<okm_u32*>(&c->finished)), 0, 0);
     }
 #else
-    const int rc = ::pthread_join(reinterpret_cast<pthread_t>(c->thread), nullptr);
+    const int rc = ::pthread_join(reinterpret_cast<void*>(
+                                      static_cast<okm_uptr>(c->thread)), nullptr);
     if (rc != 0) return translate_posix(rc);
 #endif
     kal_free(c, sizeof(context), alignof(context));