When building with component=shared_library on linux, add -rdynamic

This allows for WTF's BACKTRACE() macro to symbolize stacktraces.

BUG=none
R=glider@chromium.org

Review URL: https://codereview.chromium.org/83553002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237048 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237048