A cool idea from mbp: create a big shared library of all Samba objects

A cool idea from mbp: create a big shared library of all Samba objects
which we can use to link against Samba unit test programs.  Now we can
compile and link unit tests without having to create 4MB executables
for each program

It's called libbigballofmud.so both to discourage casual usage and
also to reflect what the dependencies within Samba have become.
(This used to be commit fdce4be719d7a81f25a4bae05934a5590038ec47)