load command that uses the Mach::source_version_command type
but not used in llvm libObject code but used in llvm tool code.
This includes just the LC_SOURCE_VERSION load command.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282736 91177308-0d34-0410-b5e6-96231b3b80d8