Remove workaround for borked sem_init library function.

src/base/platform/semaphore.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/platform/semaphore.h"
 
 #if V8_OS_MACOSX
 #include <mach/mach_init.h>
 #include <mach/task.h>
 #endif
@@ skipping 69 matching lines @@
 #if V8_OS_AIX
   // On aix sem_t is of type int
   const uintptr_t kSemaphoreAlignmentMask = sizeof(int) - 1;
 #else
   const uintptr_t kSemaphoreAlignmentMask = sizeof(void*) - 1;
 #endif
   CHECK_EQ(
       0, reinterpret_cast<uintptr_t>(&native_handle_) &
       kSemaphoreAlignmentMask);
   DCHECK(count >= 0);
-#if V8_LIBC_GLIBC
-  // sem_init in glibc prior to 2.1 does not zero out semaphores.
-  memset(&native_handle_, 0, sizeof(native_handle_));
-#endif
   int result = sem_init(&native_handle_, 0, count);
   DCHECK_EQ(0, result);
   USE(result);
 }
 
 
 Semaphore::~Semaphore() {
   int result = sem_destroy(&native_handle_);
   DCHECK_EQ(0, result);
   USE(result);
@@ skipping 105 matching lines @@
       DCHECK(result == WAIT_OBJECT_0);
       return true;
     }
   }
 }
 
 #endif  // V8_OS_MACOSX
 
 }  // namespace base
 }  // namespace v8