When possible, move __block variables to the heap rather than copying them.

Fixes <rdar://problem/13330126>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176663 91177308-0d34-0410-b5e6-96231b3b80d8
Improve LLDB's implicit cast-to-id to work with C++11 auto and any Objective-C object type <rdar://problem/13338107>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176665 91177308-0d34-0410-b5e6-96231b3b80d8