[Object] Add {begin,end}_dynamic_symbols stubs and implementation for ELF.
Add -D option to llvm-nm to dump dynamic symbols.

Patch by David Meyer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151600 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed