--- a/ipc/glue/CrossProcessSemaphore.h
+++ b/ipc/glue/CrossProcessSemaphore.h
@@ -6,17 +6,17 @@
 
 #ifndef mozilla_CrossProcessSemaphore_h
 #define mozilla_CrossProcessSemaphore_h
 
 #include "base/process.h"
 #include "mozilla/TimeStamp.h"
 #include "mozilla/Maybe.h"
 
-#if !defined(OS_WIN) && !defined(OS_NETBSD) && !defined(OS_OPENBSD) && !defined(OS_MACOSX)
+#if !defined(OS_WIN) && !defined(OS_MACOSX)
 #include <pthread.h>
 #include <semaphore.h>
 #include "SharedMemoryBasic.h"
 #include "mozilla/Atomics.h"
 #endif
 
 namespace IPC {
 template<typename T>
@@ -25,17 +25,17 @@ struct ParamTraits;
 
 //
 // Provides:
 //
 //  - CrossProcessSemaphore, a semaphore that can be shared across processes
 namespace mozilla {
 #if defined(OS_WIN)
 typedef HANDLE CrossProcessSemaphoreHandle;
-#elif !defined(OS_NETBSD) && !defined(OS_OPENBSD) && !defined(OS_MACOSX)
+#elif !defined(OS_MACOSX)
 typedef mozilla::ipc::SharedMemoryBasic::Handle CrossProcessSemaphoreHandle;
 #else
 // Stub for other platforms. We can't use uintptr_t here since different
 // processes could disagree on its size.
 typedef uintptr_t CrossProcessSemaphoreHandle;
 #endif
 
 class CrossProcessSemaphore
@@ -81,17 +81,17 @@ private:
   friend struct IPC::ParamTraits<CrossProcessSemaphore>;
 
   CrossProcessSemaphore();
   CrossProcessSemaphore(const CrossProcessSemaphore&);
   CrossProcessSemaphore &operator=(const CrossProcessSemaphore&);
 
 #if defined(OS_WIN)
   HANDLE mSemaphore;
-#elif !defined(OS_NETBSD) && !defined(OS_OPENBSD) && !defined(OS_MACOSX)
+#elif !defined(OS_MACOSX)
   RefPtr<mozilla::ipc::SharedMemoryBasic> mSharedBuffer;
   sem_t* mSemaphore;
   mozilla::Atomic<int32_t>* mRefCount;
 #endif
 };
 
 } // namespace mozilla
 

--- a/ipc/glue/moz.build
+++ b/ipc/glue/moz.build
@@ -81,17 +81,17 @@ else:
     UNIFIED_SOURCES += [
         'CrossProcessMutex_unimplemented.cpp',
     ]
 
 if CONFIG['OS_ARCH'] == 'WINNT':
     SOURCES += [
         'CrossProcessSemaphore_windows.cpp',
     ]
-elif not CONFIG['OS_ARCH'] in ('NetBSD', 'OpenBSD', 'Darwin'):
+elif CONFIG['OS_ARCH'] != 'Darwin':
     UNIFIED_SOURCES += [
         'CrossProcessSemaphore_posix.cpp',
     ]
 else:
     UNIFIED_SOURCES += [
         'CrossProcessSemaphore_unimplemented.cpp',
     ]