Make a libbigballofmud.so.0 link, so that the linker can find the

Make a libbigballofmud.so.0 link, so that the linker can find the
library to build the test cases.  Previously the link had to be
created by hand.

Doing this manually is incredibly kludgy and not very portable, but I
don't know a better way without introducing l*bt**l.
(This used to be commit 8fbe456ee34af163dddb1e6e4816ff7be4ca48f1)