Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index e52e8af..3961905 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -734,7 +734,7 @@
         object::RelocToApply R(V.visit(Type, Reloc, 0, SymAddr));
         if (V.error()) {
           SmallString<32> Name;
-          error_code ec(Reloc.getTypeName(Name));
+          std::error_code ec(Reloc.getTypeName(Name));
           if (ec) {
             errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n";
           }