[Bug c/59801] GCC does not warn on unused global variable

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59801

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This change was done on purpose.  See the patch and thread at
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg00847.html