Add missing vtable anchors

Summary: This patch adds anchor() for MemoryBuffer, raw_fd_ostream, RTDyldMemoryManager, SectionMemoryManager, etc.

Reviewers: jlebar, eli.friedman, dblaikie

Reviewed By: dblaikie

Subscribers: mehdi_amini, mgorny, dblaikie, weimingz, llvm-commits

Differential Revision: https://reviews.llvm.org/D45244

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329861 91177308-0d34-0410-b5e6-96231b3b80d8
12 files changed