[Xastir] "Fix" for Cygwin compile problem

[Bob Nielsen]

> > I had to make a change this weekend after Tom's change, as his broke
> > my compiles, due to the USE_MAP_CACHE variable not being defined
> > until after the headers are included.
> > 
> > Try moving the "#include <db.h>" line below the USE_MAP_CACHE stuff.
> 
> Heh.  And in between my change (which fixed builds without db and broke
> builds without it) and yours (which unbroke builds *with* db and re-broke 
> builds without) I installed db-4.2, so was no longer checking whether xastir 
> built without it.
> 
> Sigh. 

Dueling-CVS.  Love it!

Bob, N7XY