[Bug lto/55937] lto hides possible link issues

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55937

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2013-01-10 21:47:29 UTC ---
I think this is really invalid and the check (autoconf) should be changed
instead.  What is happening is f is known to be used outside of the program. 
If f is marked as externally_visible then it would not remove the variable f.