Minidumper: Get the nexe's build ID from PT_NOTE when available

tests/untrusted_minidump/nacl.scons

 # -*- python -*-
 # Copyright (c) 2013 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.
 
 Import('env')
 
 if env.Bit('bitcode'):
   # Preserve debugging info (which is not ABI-stable under PNaCl).
   env.SetBits('nonstable_bitcode')
 if env.Bit('skip_nonstable_bitcode'):
   Return()
 
+# Add a build ID to the nexe in the cases where this works.
+# TODO(mseaborn): Make "--build-id" work with the other toolchains.
+#  * In the x86 nacl-gcc toolchain, "--build-id" produces a nexe that
+#    sel_ldr won't load.
+#  * pnacl-ld rejects "--build-id".
+if env.Bit('build_arm') and not env.Bit('bitcode'):
+  env.Append(LINKFLAGS=['-Wl,--build-id'])
+
 nexe = env.ComponentProgram('minidump_test', 'minidump_test.c',
                             EXTRA_LIBS=['minidump_generator'])
 
 # Note that this doesn't check the crash dump that is produced yet.
 # TODO(mseaborn): Test that Breakpad can extract a stack backtrace.
 output_dump_file = env.File('minidump.dmp')
 node = env.CommandSelLdrTestNacl(
     'minidump_test.out', nexe, [output_dump_file.abspath],
     declares_exit_status=True,
     sel_ldr_flags=['-e', # Enable exception handling for catching crash
                    '-a', # Enable file access for writing minidump file
                    ])
 env.AddNodeToTestSuite(node, ['small_tests', 'exception_tests'],
                        'run_minidump_test')