Re: Issue FIXNUM-NON-PORTABLE (Version 3)

[masinter.pa@Xerox.COM]

The major reason for considering the removal of BIGNUM from the language
was that it didn't correspond to current practice in several
implementations; although all implementations had a single type which could
fit into the current and proposed definition of FIXNUM, many did not have a
single type that fit into BIGNUM. 

This is at least what led us to consider removing BIGNUM. 

We could not find programs that used the name BIGNUM.

I'm willing to split the issue into two parts, one of which says: constrain
FIXNUM and remove BIGNUM, and the other is to constrain FIXNUM and define
BIGNUM to be exactly (AND INTEGER (NOT FIXNUM)).
In the SUBTYPEP-TOO-VAGUE issue, we should probably make sure the
requirements for FIXNUM and BIGNUM are there.