Remove unused support for SysV shared memory

src/trusted/desc/nacl_desc_base.h

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * NaCl Service Runtime.  I/O Descriptor / Handle abstraction.
  */
 
@@ skipping 65 matching lines @@
 
 enum NaClDescTypeTag {
   NACL_DESC_INVALID,
   NACL_DESC_DIR,
   NACL_DESC_HOST_IO,
   NACL_DESC_CONN_CAP,
   NACL_DESC_CONN_CAP_FD,
   NACL_DESC_BOUND_SOCKET,
   NACL_DESC_CONNECTED_SOCKET,
   NACL_DESC_SHM,
-  NACL_DESC_SYSV_SHM,
   NACL_DESC_MUTEX,
   NACL_DESC_CONDVAR,
   NACL_DESC_SEMAPHORE,
   NACL_DESC_SYNC_SOCKET,
   NACL_DESC_TRANSFERABLE_DATA_SOCKET,
   NACL_DESC_IMC_SOCKET,
   NACL_DESC_QUOTA,
   NACL_DESC_DEVICE_RNG,
   NACL_DESC_DEVICE_POSTMESSAGE,
   NACL_DESC_CUSTOM,
@@ skipping 570 matching lines @@
 int NaClDescIsSafeForMmap(struct NaClDesc *self);
 
 void NaClDescMarkSafeForMmap(struct NaClDesc *self);
 
 void NaClDescMarkUnsafeForMmap(struct NaClDesc *self);
 
 
 EXTERN_C_END
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_DESC_NACL_DESC_BASE_H_