[PATCH] Fix the build of process_prefork.c

[Jeremy Allison]

On Fri, Oct 20, 2017 at 08:02:31AM +1300, Andrew Bartlett via samba-technical wrote:
> 
> Once upon a time we had a rule not to include system headers directly,
> but to bring this in via the lib/replace/system/ headers, eg
> <system/filesys.h>.
> 
> It doesn't seem to have made README.Coding however.

Do we want to add it there, and make it a formal rule ?

I have no objections.