Linking backend in one piece

Here is a patch so that the backend is linked in one piece instead of using 
the SUBSYS.o files.

The question is how we want to activate that.  I currently used make 
BIGLINK=1, which is obviously just for testing.  Should we just turn it on by 
default and see if anyone complains?

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/