Update to clang/llvm r179269 (llvm vendor branch r49215):

Parser::Scope versus Sema::DeclContext are now checked for cross-vailidity.
Emit the TU-transaction explicitly instead of relying on a first transaction.
The typename extraction now takes a stream instead of a string to write to.
The llvm::Linker has much reduced functionality; use llvm::sys::Path instead to find dynamic libraries.


git-svn-id: http://root.cern.ch/svn/root/trunk@49325 27541ba8-7e3a-0410-8455-c3a389f83636