This gives a type error (#:G1 is not a (NOT SYMBOL)) because of the
implementation of read circularity, using a symbol as a marker for
the previously-referenced object.
+
+411: NAN issues on x86-64
+ Test :NAN-COMPARISONS in float.pure.lisp fails on x86-64, and has been
+ disabled on those platforms. Since x86 does not exhibit any problems
+ the problem is probably with the new FP implementation.