diff --git a/plan9/syscall.go b/plan9/syscall.go
index b9941873..df6f8c5b 100644
--- a/plan9/syscall.go
+++ b/plan9/syscall.go
@@ -19,7 +19,7 @@
 // These calls return err == nil to indicate success; otherwise
 // err represents an operating system error describing the failure and
 // holds a value of type syscall.ErrorString.
-package plan9
+package plan9 // import "golang.org/x/sys/plan9"
 
 import "unsafe"
 
diff --git a/unix/syscall.go b/unix/syscall.go
index a48d47cf..6442a993 100644
--- a/unix/syscall.go
+++ b/unix/syscall.go
@@ -19,7 +19,7 @@
 // These calls return err == nil to indicate success; otherwise
 // err represents an operating system error describing the failure and
 // holds a value of type syscall.Errno.
-package unix
+package unix // import "golang.org/x/sys/unix"
 
 import "unsafe"
 
diff --git a/windows/syscall.go b/windows/syscall.go
index 281cd669..a8cc609b 100644
--- a/windows/syscall.go
+++ b/windows/syscall.go
@@ -19,7 +19,7 @@
 // These calls return err == nil to indicate success; otherwise
 // err represents an operating system error describing the failure and
 // holds a value of type syscall.Errno.
-package windows
+package windows // import "golang.org/x/sys/windows"
 
 import (
 	"syscall"