This change fixed link errors in building shared library
for android. crtbegin_so.o is added to resolve dso_handle
and exclude-libs option is removed for shared library.

Review URL: https://chromiumcodereview.appspot.com/11262003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12806 ce2b1a6d-e550-0410-aec6-3dcde31c8c00