/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/ is in llvm-6.0-dev 1:6.0-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/CompileUtils.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/ExecutionUtils.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/GlobalMappingLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/IRCompileLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/IRTransformLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/IndirectionUtils.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/LambdaResolver.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/LazyEmittingLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/NullResolver.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/ObjectTransformLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/OrcABISupport.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/OrcError.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/OrcRemoteTargetRPCAPI.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/OrcRemoteTargetServer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/RPCSerialization.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/RPCUtils.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/RawByteChannel.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/RemoteObjectLayer.h
/usr/include/llvm-6.0/llvm/ExecutionEngine/Orc/SymbolStringPool.h