[pptp-server] Trivial yet major bug

[David Luyer]

> I found the compile message later, but (wait for this!), under OpenBSD
> -ansi causes me problems with the macros that contribute to htons().

Annoying.  Keeping ansi-clean code is really good for portability to platforms 
without needing gcc (eg, on OSF/1, IRIX or Solaris without gcc).

I'll put in the "static" on all the things -Wmissing-prototypes picks up (if
you haven't already).

> Can a Makefile.am have conditional logic in it ?