runtime/internal/lib/os: fix readdir for darwin-amd64

runtime/internal/clite/os/dir.go

@@ -0,0 +1,17 @@
+package os
+
+import (
+	_ "unsafe"
+
+	c "github.com/goplus/llgo/runtime/internal/clite"
+)
+
+type DIR struct {
+	Unused [0]byte
+}
+
+//go:linkname Opendir C.opendir
+func Opendir(name *c.Char) *DIR
+
+//go:linkname Closedir C.closedir
+func Closedir(dir *DIR) c.Int