LinkOnce definitions have default scope, like weak definitions. Otherwise, the linker...

LinkOnce definitions have default scope, like weak definitions. Otherwise, the linker may not be able to match LinkOnce definition from one module with an exteranl reference from other module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53580 91177308-0d34-0410-b5e6-96231b3b80d8