build: separate compiler and libs

compiler/internal/lib/os/wait_wait6.go

@@ -0,0 +1,32 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build dragonfly || freebsd || netbsd
+
+package os
+
+import (
+	"syscall"
+)
+
+// blockUntilWaitable attempts to block until a call to p.Wait will
+// succeed immediately, and reports whether it has done so.
+// It does not actually call p.Wait.
+func (p *Process) blockUntilWaitable() (bool, error) {
+	var errno syscall.Errno
+	for {
+		_, errno = wait6(_P_PID, p.Pid, syscall.WEXITED|syscall.WNOWAIT)
+		if errno != syscall.EINTR {
+			break
+		}
+	}
+	// TODO(xsw):
+	// runtime.KeepAlive(p)
+	if errno == syscall.ENOSYS {
+		return false, nil
+	} else if errno != 0 {
+		return false, NewSyscallError("wait6", errno)
+	}
+	return true, nil
+}