Change all uses of LIB in UNIX makefiles to LIBBASE, for better Windows

Change all uses of LIB in UNIX makefiles to LIBBASE, for better Windows
compatibility.  (Windows nmake exports make variables into the environment, and
LIB is treated by the Windows linker as a search path for libraries, thus
breaking the linking on Windows of anything needing libraries from the search
path in directories where we build libraries on UNIX.)

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16411 dc483132-0cff-0310-8789-dd5450dbe970