Fix potential error in boolean?

It's the same as for char?, only here I didn't find a case for which it
happened yet.

scm/inc/compiler.scm

@@ -73,7 +73,7 @@
        (emit-compare))
       ((boolean?)
        (emit-expr (primcall-operand1 x))
        (emit "andl $~a, %eax" #b0011111)
        (emit "andl $~a, %eax" #b1111111)
        (emit "cmpl $~a, %eax" #b0011111)
        (emit-compare))
       ))))