Switch Sema::UnusedFileScopedDecls over to a LazyVector. 
  - Added LazyVector::erase() to support this use case.
  - Factored out the LazyDecl-of-Decls to RecordData translation in
  the ASTWriter. There is still a pile of code duplication here to
  eliminate.

llvm-svn: 136270
7 files changed
tree: ce1c7a88e144c32cd240074f8f0fb656ddca7ef6
  1. clang/
  2. compiler-rt/
  3. debuginfo-tests/
  4. libcxx/
  5. libcxxabi/
  6. lldb/
  7. llvm/
  8. polly/