Add libstdc++6-4.6-dbg to build deps.

build/install-build-deps.sh

 #!/bin/bash -e
 
 # 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.
 
 # Script to install everything needed to build chromium (well, ideally, anyway)
 # See http://code.google.com/p/chromium/wiki/LinuxBuildInstructions
 # and http://code.google.com/p/chromium/wiki/LinuxBuild64Bit
 
@@ skipping 104 matching lines @@
           libxau6 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxdmcp6
           libxext6 libxfixes3 libxi6 libxinerama1 libxrandr2 libxrender1
           libxtst6 zlib1g $chromeos_lib_list"
 
 # Debugging symbols for all of the run-time libraries
 dbg_list="libatk1.0-dbg libc6-dbg libcairo2-dbg libfontconfig1-dbg
           libglib2.0-0-dbg libgtk2.0-0-dbg libpango1.0-0-dbg libpcre3-dbg
           libpixman-1-0-dbg libsqlite3-0-dbg libx11-6-dbg libxau6-dbg
           libxcb1-dbg libxcomposite1-dbg libxcursor1-dbg libxdamage1-dbg
           libxdmcp6-dbg libxext6-dbg libxfixes3-dbg libxi6-dbg libxinerama1-dbg
-          libxrandr2-dbg libxrender1-dbg libxtst6-dbg zlib1g-dbg"
+          libxrandr2-dbg libxrender1-dbg libxtst6-dbg zlib1g-dbg
+          libstdc++6-4.6-dbg"
 
 # arm cross toolchain packages needed to build chrome on armhf
 arm_list="libc6-armhf-cross libc6-dev-armhf-cross libgcc1-armhf-cross
           libgomp1-armhf-cross linux-libc-dev-armhf-cross
           libgcc1-dbg-armhf-cross libgomp1-dbg-armhf-cross
           binutils-arm-linux-gnueabihf cpp-arm-linux-gnueabihf
           gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf
           libmudflap0-dbg-armhf-cross"
 
 # Old armel cross toolchain packages
@@ skipping 430 matching lines @@
              sed -e 's/[.]so[.][0-9].*/.so/' |
              sort -u); do
     [ "x${i##*/}" = "xld-linux.so" ] && continue
     [ -r "$i" ] && continue
     j="$(ls "$i."* | sed -e 's/.*[.]so[.]\([^.]*\)$/\1/;t;d' |
          sort -n | tail -n 1)"
     [ -r "$i.$j" ] || continue
     sudo ln -s "${i##*/}.$j" "$i"
   done
 fi