that it's equal to 1. (If isinf isn't defined, HAVE_DECL_ISINF is
defined to be 0, rather than being undefined.)
* Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
*/
#ifndef Py_IS_NAN
-#ifdef HAVE_DECL_ISNAN
+#ifdef HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
#define Py_IS_NAN(X) isnan(X)
#else
#define Py_IS_NAN(X) ((X) != (X))
* Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
*/
#ifndef Py_IS_INFINITY
-#ifdef HAVE_DECL_ISINF
+#ifdef HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
#define Py_IS_INFINITY(X) isinf(X)
#else
#define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))