[Orc] Move Orc code into a namespace (llvm::orc), update Kaleidoscope code.

NFC.

llvm-svn: 230143
diff --git a/llvm/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp b/llvm/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp
index 75d1b1f..48fd31e 100644
--- a/llvm/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp
@@ -13,7 +13,7 @@
 namespace {
 
 static struct RegisterJIT {
-  RegisterJIT() { llvm::OrcMCJITReplacement::Register(); }
+  RegisterJIT() { llvm::orc::OrcMCJITReplacement::Register(); }
 } JITRegistrator;
 
 }
@@ -21,6 +21,7 @@
 extern "C" void LLVMLinkInOrcMCJITReplacement() {}
 
 namespace llvm {
+namespace orc {
 
 GenericValue
 OrcMCJITReplacement::runFunction(Function *F,
@@ -122,4 +123,6 @@
 
   llvm_unreachable("Full-featured argument passing not supported yet!");
 }
-}
+
+} // End namespace orc.
+} // End namespace llvm.