Update comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191720 91177308-0d34-0410-b5e6-96231b3b80d8
Add the DW_AT_GNU_ranges_base attribute if we've emitted any ranges
into the debug_ranges section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191721 91177308-0d34-0410-b5e6-96231b3b80d8