feat(c/os): restore common native OS APIs

c/os/_libc_darwin_arm64.c

@@ -0,0 +1,60 @@
+// Code generated by llcppg; classified from the common libc binding.
+#include <arpa/inet.h>
+#include <assert.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <fnmatch.h>
+#include <glob.h>
+#include <grp.h>
+#include <inttypes.h>
+#include <libgen.h>
+#include <limits.h>
+#include <locale.h>
+#include <net/if.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <pthread.h>
+#include <pwd.h>
+#include <sched.h>
+#include <semaphore.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/file.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+#include <sys/utsname.h>
+#include <sys/wait.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+#include <utime.h>
+#include <mach/mach_types.h>
+
+int _llcppg___darwin_check_fd_set(int _a, const void *_b) {
+	return __darwin_check_fd_set(_a, _b);
+}
+
+int _llcppg___darwin_fd_isset(int _fd, const struct fd_set *_p) {
+	return __darwin_fd_isset(_fd, _p);
+}

c/os/dir.go

@@ -14,6 +14,3 @@ type DIR struct {
 
 //go:linkname Opendir C.opendir
 func Opendir(name *c.Char) *DIR
-
-//go:linkname Closedir C.closedir
-func Closedir(dir *DIR) c.Int

c/os/dirent_unix64.go

@@ -0,0 +1,8 @@
+//go:build (darwin && arm64 && !ios) || (linux && amd64 && !android)
+
+package os
+
+import "github.com/goplus/lib/c/syscall"
+
+// Dirent shares the representation already used by Readdir.
+type Dirent = syscall.Dirent

c/os/flags_default.go

@@ -1,4 +1,4 @@
-//go:build !windows
+//go:build !windows && !(linux && (amd64 || arm64) && !android)
 
 /*
  * Copyright (c) 2026 The XGo Authors (xgo.dev). All rights reserved.

c/os/functions_default.go

@@ -27,12 +27,6 @@ func Getcwd(buffer c.Pointer, size uintptr) *c.Char
 //go:linkname Open C.open
 func Open(path *c.Char, flags c.Int, __llgo_va_list ...any) c.Int
 
-//go:linkname Fcntl C.fcntl
-func Fcntl(a c.Int, b c.Int, __llgo_va_list ...any) c.Int
-
-//go:linkname Close C.close
-func Close(fd c.Int) c.Int
-
 //go:linkname Read C.read
 func Read(fd c.Int, buf c.Pointer, count uintptr) int
 

c/os/generated_native_darwin_arm64_llgo_test.go

@@ -0,0 +1,30 @@
+//go:build llgo && darwin && arm64 && !ios
+
+package os
+
+import (
+	"testing"
+	"unsafe"
+)
+
+func TestGeneratedMachMessageHeaderLayout(t *testing.T) {
+	var header MachMsgHeaderT
+	if unsafe.Sizeof(header) != 24 || unsafe.Alignof(header) != 4 {
+		t.Fatalf("mach_msg_header_t = %d/%d, want 24/4", unsafe.Sizeof(header), unsafe.Alignof(header))
+	}
+}
+func TestGeneratedUUIDOutputBuffer(t *testing.T) {
+	var value UuidT
+	for i := range value {
+		value[i] = 0xa5
+	}
+	UuidClear(&value[0])
+	for i, b := range value {
+		if b != 0 {
+			t.Fatalf("uuid_clear left byte %d = %d", i, b)
+		}
+	}
+	if result := UuidIsNull(&value[0]); result == 0 {
+		t.Fatal("cleared uuid is not nil")
+	}
+}

c/os/generated_native_llgo_test.go

@@ -0,0 +1,42 @@
+//go:build llgo && ((darwin && arm64 && !ios) || (linux && (amd64 || arm64) && !android))
+
+package os
+
+import (
+	"github.com/goplus/lib/c"
+	"testing"
+	"unsafe"
+)
+
+func TestGeneratedPipeIO(t *testing.T) {
+	var pair [2]c.Int
+	if result := NativePipe(&pair[0]); result != 0 {
+		t.Fatalf("pipe = %d", result)
+	}
+	defer func() {
+		for _, fd := range pair {
+			if result := Close(fd); result != 0 {
+				t.Errorf("close = %d", result)
+			}
+		}
+	}()
+	input := [6]byte{0, 1, 127, 128, 254, 255}
+	var output [6]byte
+	for offset := 0; offset < len(input); {
+		n := NativeWrite(pair[1], unsafe.Pointer(&input[offset]), c.SizeT(len(input)-offset))
+		if n <= 0 {
+			t.Fatalf("write = %d", n)
+		}
+		offset += int(n)
+	}
+	for offset := 0; offset < len(output); {
+		n := NativeRead(pair[0], unsafe.Pointer(&output[offset]), c.SizeT(len(output)-offset))
+		if n <= 0 {
+			t.Fatalf("read = %d", n)
+		}
+		offset += int(n)
+	}
+	if output != input {
+		t.Fatalf("pipe data = %v, want %v", output, input)
+	}
+}

c/os/legacy_functions_other.go

@@ -0,0 +1,38 @@
+//go:build !windows && !((darwin && arm64 && !ios) || (linux && (amd64 || arm64) && !android))
+
+package os
+
+import (
+	"github.com/goplus/lib/c"
+	_ "unsafe"
+)
+
+//go:linkname Closedir C.closedir
+func Closedir(dir *DIR) c.Int
+
+//go:linkname Close C.close
+func Close(fd c.Int) c.Int
+
+//go:linkname Fchdir C.fchdir
+func Fchdir(dirfd c.Int) c.Int
+
+//go:linkname Dup C.dup
+func Dup(fd c.Int) c.Int
+
+//go:linkname Dup2 C.dup2
+func Dup2(oldfd c.Int, newfd c.Int) c.Int
+
+//go:linkname Fsync C.fsync
+func Fsync(fd c.Int) c.Int
+
+//go:linkname Isatty C.isatty
+func Isatty(fd c.Int) c.Int
+
+// In Mach, all system calls take normal arguments and always return an
+// error code (zero for success).
+//
+//go:linkname Syscall C.syscall
+func Syscall(sysno c.Long, __llgo_va_list ...any) c.Long
+
+//go:linkname Fcntl C.fcntl
+func Fcntl(a c.Int, b c.Int, __llgo_va_list ...any) c.Int