/usr/include/x86_64-linux-gnu/ is in linux-libc-dev 4.4.0-21.37.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/asm/
/usr/include/x86_64-linux-gnu/asm/a.out.h
/usr/include/x86_64-linux-gnu/asm/auxvec.h
/usr/include/x86_64-linux-gnu/asm/bitsperlong.h
/usr/include/x86_64-linux-gnu/asm/boot.h
/usr/include/x86_64-linux-gnu/asm/bootparam.h
/usr/include/x86_64-linux-gnu/asm/byteorder.h
/usr/include/x86_64-linux-gnu/asm/debugreg.h
/usr/include/x86_64-linux-gnu/asm/e820.h
/usr/include/x86_64-linux-gnu/asm/errno.h
/usr/include/x86_64-linux-gnu/asm/fcntl.h
/usr/include/x86_64-linux-gnu/asm/hw_breakpoint.h
/usr/include/x86_64-linux-gnu/asm/hyperv.h
/usr/include/x86_64-linux-gnu/asm/ioctl.h
/usr/include/x86_64-linux-gnu/asm/ioctls.h
/usr/include/x86_64-linux-gnu/asm/ipcbuf.h
/usr/include/x86_64-linux-gnu/asm/ist.h
/usr/include/x86_64-linux-gnu/asm/kvm.h
/usr/include/x86_64-linux-gnu/asm/kvm_para.h
/usr/include/x86_64-linux-gnu/asm/kvm_perf.h
/usr/include/x86_64-linux-gnu/asm/ldt.h
/usr/include/x86_64-linux-gnu/asm/mce.h
/usr/include/x86_64-linux-gnu/asm/mman.h
/usr/include/x86_64-linux-gnu/asm/msgbuf.h
/usr/include/x86_64-linux-gnu/asm/msr-index.h
/usr/include/x86_64-linux-gnu/asm/msr.h
/usr/include/x86_64-linux-gnu/asm/mtrr.h
/usr/include/x86_64-linux-gnu/asm/param.h
/usr/include/x86_64-linux-gnu/asm/perf_regs.h
/usr/include/x86_64-linux-gnu/asm/poll.h
/usr/include/x86_64-linux-gnu/asm/posix_types.h
/usr/include/x86_64-linux-gnu/asm/posix_types_32.h
/usr/include/x86_64-linux-gnu/asm/posix_types_64.h
/usr/include/x86_64-linux-gnu/asm/posix_types_x32.h
/usr/include/x86_64-linux-gnu/asm/prctl.h
/usr/include/x86_64-linux-gnu/asm/processor-flags.h
/usr/include/x86_64-linux-gnu/asm/ptrace-abi.h
/usr/include/x86_64-linux-gnu/asm/ptrace.h
/usr/include/x86_64-linux-gnu/asm/resource.h
/usr/include/x86_64-linux-gnu/asm/sembuf.h
/usr/include/x86_64-linux-gnu/asm/setup.h
/usr/include/x86_64-linux-gnu/asm/shmbuf.h
/usr/include/x86_64-linux-gnu/asm/sigcontext.h
/usr/include/x86_64-linux-gnu/asm/sigcontext32.h
/usr/include/x86_64-linux-gnu/asm/siginfo.h
/usr/include/x86_64-linux-gnu/asm/signal.h
/usr/include/x86_64-linux-gnu/asm/socket.h
/usr/include/x86_64-linux-gnu/asm/sockios.h
/usr/include/x86_64-linux-gnu/asm/stat.h
/usr/include/x86_64-linux-gnu/asm/statfs.h
/usr/include/x86_64-linux-gnu/asm/svm.h
/usr/include/x86_64-linux-gnu/asm/swab.h
/usr/include/x86_64-linux-gnu/asm/termbits.h
/usr/include/x86_64-linux-gnu/asm/termios.h
/usr/include/x86_64-linux-gnu/asm/types.h
/usr/include/x86_64-linux-gnu/asm/ucontext.h
/usr/include/x86_64-linux-gnu/asm/unistd.h
/usr/include/x86_64-linux-gnu/asm/unistd_32.h
/usr/include/x86_64-linux-gnu/asm/unistd_64.h
/usr/include/x86_64-linux-gnu/asm/unistd_x32.h
/usr/include/x86_64-linux-gnu/asm/vm86.h
/usr/include/x86_64-linux-gnu/asm/vmx.h
/usr/include/x86_64-linux-gnu/asm/vsyscall.h