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/Bitcode/Reader/BitReader.cpp b/lib/Bitcode/Reader/BitReader.cpp
index 716299f..b5886c1 100644
--- a/lib/Bitcode/Reader/BitReader.cpp
+++ b/lib/Bitcode/Reader/BitReader.cpp
@@ -32,7 +32,7 @@
                                    char **OutMessage) {
   ErrorOr<Module *> ModuleOrErr =
       parseBitcodeFile(unwrap(MemBuf), *unwrap(ContextRef));
-  if (error_code EC = ModuleOrErr.getError()) {
+  if (std::error_code EC = ModuleOrErr.getError()) {
     if (OutMessage)
       *OutMessage = strdup(EC.message().c_str());
     *OutModule = wrap((Module*)nullptr);
@@ -54,7 +54,7 @@
   ErrorOr<Module *> ModuleOrErr =
       getLazyBitcodeModule(unwrap(MemBuf), *unwrap(ContextRef));
 
-  if (error_code EC = ModuleOrErr.getError()) {
+  if (std::error_code EC = ModuleOrErr.getError()) {
     *OutM = wrap((Module *)nullptr);
     if (OutMessage)
       *OutMessage = strdup(EC.message().c_str());