diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index b8257768ac3..78557759ccb 100644
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -7,6 +7,7 @@ package runtime
 import "unsafe"
 
 type mOS struct {
+	machport uint32 // return address for mach ipc
 	waitsema uint32 // semaphore for parking on locks
 }
 
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 379fe2678b3..5bc5fca7f0d 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -309,7 +309,6 @@ type m struct {
 	park          note
 	alllink       *m // on allm
 	schedlink     muintptr
-	machport      uint32 // return address for mach ipc (os x)
 	mcache        *mcache
 	lockedg       *g
 	createstack   [32]uintptr // stack that created this thread.