drop unused execinfo.h header

base/debug/debugger_posix.cc

 // Copyright (c) 2012 The Chromium 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 "base/debug/debugger.h"
 #include "build/build_config.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <string>
 #include <vector>
 
-#if !defined(OS_ANDROID) && !defined(OS_NACL)
-#include <execinfo.h>
-#endif
-
 #if defined(__GLIBCXX__)
 #include <cxxabi.h>
 #endif
 
 #if defined(OS_MACOSX)
 #include <AvailabilityMacros.h>
 #endif
 
 #if defined(OS_MACOSX) || defined(OS_BSD)
 #include <sys/sysctl.h>
@@ skipping 222 matching lines @@
   // attach the debugger, inspect the state of the program and then resume it by
   // setting the 'go' variable above.
 #elif defined(NDEBUG)
   // Terminate the program after signaling the debug break.
   _exit(1);
 #endif
 }
 
 }  // namespace debug
 }  // namespace base