Summary:
Only allow a single unique .symver alias per symbol. This matches the
behavior of gas. I noticed that we ignored multiple mismatched symver
directives looking at https://reviews.llvm.org/D45798
Reviewers: pcc, tejohnson, espindola
Reviewed By: pcc
Subscribers: emaste, arichardson, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D45845
llvm-svn: 331078
Vlad Tsyrklevich