This #ifdef'd code clearly doesn't get compiled, as it would fail.
# define Perl_fp_class_snan(x) (_fpclass(x) & _FPCLASS_SNAN)
# define Perl_fp_class_qnan(x) (_fpclass(x) & _FPCLASS_QNAN)
# define Perl_fp_class_nan(x) (_fpclass(x) & (_FPCLASS_SNAN|_FPCLASS_QNAN))
-# define Perl_fp_class_ninf(x) (_fpclass(x) & _FPCLASS_NINF))
-# define Perl_fp_class_pinf(x) (_fpclass(x) & _FPCLASS_PINF))
+# define Perl_fp_class_ninf(x) (_fpclass(x) & _FPCLASS_NINF)
+# define Perl_fp_class_pinf(x) (_fpclass(x) & _FPCLASS_PINF)
# define Perl_fp_class_inf(x) (_fpclass(x) & (_FPCLASS_NINF|_FPCLASS_PINF))
# define Perl_fp_class_nnorm(x) (_fpclass(x) & _FPCLASS_NN)
# define Perl_fp_class_pnorm(x) (_fpclass(x) & _FPCLASS_PN)