Remove emulate.o for now.

While we work on a different thing.

Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Remove unused UINT64 macro

This is interfering with other definitions in user code.
If we ever want Ivy back we can conditionally include
ivy.h
based on a config variable or something, right?

Signed-off-by: Ronald G. Minnich <rminnich@google.com>