Spec says "A hidden symbol contained in a relocatable object must be either
removed or converted to STB_LOCAL binding by the link-editor when the
relocatable object is included in an executable file or shared object".
But we previously converted symbols to STB_LOCAL even when -r was specified.
Broken binary was produced, this is PR28967, patch fixes the issue.
Differential revision: https://reviews.llvm.org/D23514
llvm-svn: 279220