Moon's floating-point extractors proposal

[Guy.Steele at CMU-10A]

I support Moon's proposal, but would like to suggest that FLOAT-SIGN
be modified to
	(FLOAT-SIGN x &optional (y (float 1 x)))
	returns z such that x and z have same sign and (= (abs y) (abs z)).
In this way (FLOAT-SIGN x) returns 1.0 or -1.0 of the same format as x,
and FLOAT-SIGN of two arguments is what the IEEE proposal calls COPYSIGN,
a useful function indeed in numerical code.
--Guy