Misc op5 fixes

This is a bit of a mixed bag of commits.

The first half are proper bug fixes that I've ported from op5's patchqueue for nagios ( http://git.op5.org/gitweb?p=monitor%2Fnagios.git;a=shortlog;h=HEAD )

The latter half were written while packaging naemon core. They are there to "make more things more standard".
I know that this change solves some problems, but wouldn't it be better to change buildopts.h.in? (I haven't lookt at that file though...) That would mean variables contains the same string all the time...

I won't reject the patch for those lines, but I believe that this is one of those patches someone (probably yourself) would stare at and wonder "what the heck?" in a couple of months...