Prefer common over weak linkage when linking.

This matches the behavior of ELF linkers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217443 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a use of an undefined value (the linkage).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217445 91177308-0d34-0410-b5e6-96231b3b80d8
LLVMProfileData: Update LLVMBuild.txt corresponding to r217437.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217446 91177308-0d34-0410-b5e6-96231b3b80d8
ScalarOpts/LLVMBuild.txt: Reorder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217447 91177308-0d34-0410-b5e6-96231b3b80d8
ScalarOpts/LLVMBuild.txt: Prune unused dependency to IPA.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217448 91177308-0d34-0410-b5e6-96231b3b80d8