zlib multilib on host?

[David Edelsohn]

	By default, zlib configures as multilib.  Why is this correct for
the gcc bulid and host?  The compiler will not itself be built as a
multilib and the multilibs of the bootstrap compiler do not necessary
correspond to the multilibs of the target.

	I could understand zlib configuring as multilib when building the
target multilib libraries (in the target library directory of the object
tree), but not the top-level object tree directory.

	What is going on?

Thanks, David