[PATCH 2.26 backport] PR gold/19047: Fix bug related to addend computation for MERGE sections.

[Roland McGrath]

Trunk commit 8fe0f303f4d792ab581483be69d448574bbd4835 applies cleanly
to the 2.26 branch.
I'd like to push cherry-pick -x of that to the branch.  It fixes 19047.  OK?

Unfortunately the ChangeLog entry in the trunk fix did not mention the
bugzilla #.
Should I just leave it as it is, or should I amend the ChangeLog
message in the cherry-pick?


Thanks,
Roland