[Chromecast] Include all stdlibc++/libgcc symbols in cast_shell.

build/common.gypi

 # 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 4131 matching lines @@
                       # '-march=armv7-a' is actually redundant anyway because
                       # it is enabled by default when we built the toolchain.
                       # And using '-mcpu=cortex-a9' should be sufficient.
                       '-mcpu=cortex-a9',
                       '-funwind-tables',
                       # Breakpad requires symbols with debugging information
                       '-g',
                     ],
                     'ldflags': [
                       # We want to statically link libstdc++/libgcc_s.
+                      # Export the libstdc++ symbols so multiple copies merge
+                      # at runtime.
+                      '-Wl,--export-dynamic',

[slan, 2015/12/01 19:29:32]

If we go this route, this needs to be echoed in GN.

[bcf, 2015/12/01 19:52:30]

Done.

                       '-static-libstdc++',
                       '-static-libgcc',
                     ],
                     'cflags!': [
                       # Some components in Chromium (e.g. v8, skia, ffmpeg)
                       # define their own cflags for arm builds that could
                       # conflict with the flags we set here (e.g.
                       # '-mcpu=cortex-a9'). Remove these flags explicitly.
                       '-march=armv7-a',
                       '-mtune=cortex-a8',
                     ],
+                    'target_conditions': [
+                      [ '_type=="executable"', {
+                        # Statically link whole libstdc++ and libgcc in
+                        # executables to ensure only one copy at runtime.
+                        'ldflags': [
+                          '-lm', # stdlibc++ requires math.h
+
+                          # In case we redefined stdlibc++ symbols
+                          # (e.g. tc_malloc)
+                          '-Wl,--allow-multiple-definition',
+
+                          '-Wl,--whole-archive',
+                          '-l:libstdc++.a',
+                          '-l:libgcc.a',
+                          '-Wl,--no-whole-archive',
+                        ],
+                      }]
+                    ],
                   }],
                 ],
               }],
             ],
           }],
           ['target_arch=="arm64"', {
             'target_conditions': [
               ['_toolset=="target"', {
                 'conditions': [
                   ['OS=="android"', {
@@ skipping 2200 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }