Add MAP_FIXED_NOREPLACE from Linux 4.17 to bits/mman.h

[Florian Weimer]

On 06/04/2018 11:29 PM, Joseph Myers wrote:
> Linux 4.17 adds MAP_FIXED_NOREPLACE (value 0x100000 on most
> architectures, 0x200000 on alpha).  This patch adds that macro to
> glibc's bits/mman.h headers.

Patch looks good to me.  Thanks.

Florian