This help to streamline the process of handling importing since
we don't need to special case alias everywhere: just like
linkonce_odr function, make sure at least one alias is emitted
by turning it weak.
Differential Revision: http://reviews.llvm.org/D19308
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266958
Mehdi Amini